A long while ago I compiled advice from various postings here (37 posts I think) at EnWorld on playing a Druid. Some of the advice is bad, some good, some probably contradictory. I'm not vouching for the veracity of any of it, but perhaps you will find some of it helpful:
1) Take one level of monk. Several reasons. First, a druid will be advancing her wisdom over time, and by taking one level of monk you are enabling a gradual AC improvement over time, AC that will remain with you in Wildshaped form since you retain your mental faculties when wildshaped. Evasion is sweet also, not to mention the overall +6 boost to your saving throws. You do need to deal with the alignment issue (monks must be lawful) but for pure minmaxing this isn't all that important. Some might say go 4 levels as a monk to gain extra movement/AC/other special abilities but I personally believe that when you plan on primarily being a spellcasting type you should severely limit your multiclassing; otherwise you give up your most potent (highest level) spells.
1a) Alternate: take one level of barbarian
The rage and the added movement (as well as the slight boost in HP) will all help when you go into battle, including when you do so in animal form.
2) Talk to your DM about Animal companions.
In order to be balanced with other classes in overall ability, it is vital that the druid be permitted to obtain and freely use the animal companion(s). In campaigns where the DM either does not allow the use of the animal companion or the animal dilutes the experience award, the value of the druid is diminished noticeably.
3) Take the Scribe Scroll feat
Certain druid spells (Call Lightning is the absolute perfect example) are only useful in certain circumstances but at those times can turn the tide in the party's favor. Keep scrolls of such spells on hand rather than pick them on a daily basis
4) Be prepared to fight
The druid is a suprisingly weak combat spellcaster unless the circumstances are right, ala Entangle. While they have a fairly good number of spells, many are of very limited use in combat, and/or are not much better than engaging in weapon combat. Keep that in mind, and choose feats/skills/ability scores carefully with the thought in mind that you will probably need to spend some time fighting. Working out combat tactics like standing in your own Flaming Sphere while protected by Endure Elements: Fire when in combat can go along way towards keeping you effective.
5) Enhance your animal forms
Starting at level 5, you can Wildshape, and these forms are often better than your own for fighting in. The dodge/mobility/spring attack feat path is an extremely good one for a druid who plans on fighting in animal form - you will tend to have good movement and decent attacks but poor AC, so the "hit and run" nature of Spring Attack makes it a natural choice for the minmaxing druid.
6) Know your animals/animal forms
Certain animals are good for certain things. A Wolf for example isn't the greatest combatant, but is excellent for chasing down fleeing opponents, using the Trip attack to slow them down so you can catch up. The Dire Bat has a wonderful AC. The ape has the strength to bend bars and batter down doors. Etc Etc. Chart out the animals you can summon/transform into/take as companions, because the different animals are useful for different roles, and it isn't all about HD and attacks.
7) Wands
A Wand of Entangle and another of Cure Light Wounds is a near-necessity.
8) Take Tracking
Tracking is an excellent feat for a druid, especially one without a Ranger, for several reasons. First, the skill on which it operates is a primary druid skill, it is Wisdom based (this should be your best score), and in many animal forms you will gain the benefit of Tracking enhancement senses, like Scent.
9) Talk to your DM before taking ranks in Knowlege: Nature.
You will certainly want Wilderness Lore, and these two skills overlap to an extent.
10) If you intend to rely on armour (ie you don't go the monk route suggested above) make sure you press your DM about maing armour from hides of tougher creatures you face: Scale Mail made from Dragon scales, Banded mail made from Ankheg carapace, Hide or Leather armour made from Aurumvorax, and/or shields made from Bulette crests. These are all nonmetallic variants that a reasonable DM should consider for use as armour. Don't expect to get the same natural AC as these creatures, and expect to pay a mint for a smith to do the job if you can get the DM to agree to it.
11) Sleep in unused animal forms
You are under most circumstances a lot safer inside a squirrel hole in a tree or down an old mole hole than sleeping around the campfire with the other party members. If on watch, your senses will generally be better as an animal of the appropriate type than as a humanoid.
12) Press for DotF
Defenders of the Faith contains a few nice spells available to druids, including an Entangle variant that damages those caught in it. Talk to your DM about making those spells official for your campaign.
13) To Awaken, or Not:
DMs have varying opinions about what happens to your Animal companion when you cast the 4th level spell "Awaken" on him. Some will say he becomes an NPC and is no longer your companion, others will say he still is but can now gain character levels due to intelligence. Know in advance what effect this will have on your companions, and plan accordingly.
14) Monk combined with druid isn't so bad. Just use the totalled BAB - don't worry about more favorable -3 iterative attacks.
Take a total of like 7 levels of monk, and the rest druid. Greater magic fang + shapechange + monk abilities (stunning attack, etc, etc). Shapechange into a dire bear and let fly with stunning attacks and what not. Put your best stats into wisdom then dexterity in that order. Start off by taking 9 levels of druid, very first, so you can get large wildshapes. Then start with monk levels up to 7-ish. Alternate thereafter.
15) Use wildshape to compensate for low physical scores (str, con). Use greater magic fang to hit magically. Then you can do nasty things like this, at around 15th level:
Greater magic fang to make whatever a +3 weapon (bite is good). Wildshape into a polar bear for 27 str, 19 con and +5 natural armor and base 2d8 bite damage. Do things like this:
Improved trip (+12 to your opposed trip check - 8 + 4 for size), bite for 2d8+11 (+8 +3) as a stunning attack at dc 17 or so (1/2 of 6th level monk + 4 for 18 wisdom by 15th level), then use improved grab to make this a free grapple attempt. This is ONE attack total. You can do this at least twice a round (you BAB is +10 though, one away from a third). You can even use flurry of blows with your natural weapons to get an extra attack at -2 to all attacks
So your attacks could be at +19/+19/+14 (+10+8+3-2), dealing 2d8+11. Anywho, that's from the minmax man (and note that NOWHERE does it say that flurry of blows is restricted to using your monk unarmed BAB
I checked. Repeatedly.) This makes the three-section staff combined with 4 monk/16 druid a NASTY NASTY NASTY combo - basically two weapon fighting but with 1.5x str bonus applied to every attack. Monk/druid, the most overlooked combo in the PHB Even moreso than paladin/sorcerer (which is nowhere near as cool). Oh, one last note, in polar form, assuming 18 wis and the form's 13 dex, your AC would be base: +4+1+5-1+1 = 20. Plus any deflection bonuses you can acquire, or expertise or whatever. Should be able to get better than 18 wisdom by 15th level, too
16) I would stay straight classed druid until at least 5th level, more likely 9th. Though if your group is awfully fighter light you might want to take 4 levels of monk first, followed by a whole lot of druid levels. Depends mainly on what your group needs. If you're caster light, take druid to 9th first, if not take monk to 4th first. All in all though I find it's easiest to get caster levels out of the way as early as possible, since while a level of a fighting class means the same at almost any level, really, caster levels mean a lot less at higher level. Say for example you're a 9th level wizard and you take 1 level of fighter. This ups your bab one, gives you martial weapons, a bonus feat, 1d10 hps. Say you're a 9th level fighter, and you take 1 level of wizard. This gives you - sleep. Or 1d4+1 magic missile. Or color spray(one of the coolest lowbie spells). None of which compare to taking that 10th level of fighter - a bonus feat, another bab, 1d10 instead of 1d4 hps.
That's my rationale for getting your druid levels out of the way ASAP. Taking one level of monk for saves and evasion can't hurt you much, but I wouldn't go much further than that. Honestly though I would go druid 9, monk 6, druid rest
17) At first level, with TWF and Ambidexterity a 1st level Druid who casts Shilelagh on a Quarterstaff gets two attacks per round at 1d10+1 each.
At third level, a Druid gets Barkskin which gives him a natural AC bonus which is cumulative with everything.
At fifth level, a Druid gets shapechange and so can fly, swim, climb, and basically go nearly anywhere with impunity, disguised.
At seventh level, a Druid can cast the lowest level 'bring back from dead' spell in the game. As a natural shapeshifter, he is minimally affected by the side effects.
At ninth level, he is the only class to get 'Awaken' with which he can create an army of intelligent animals and trees and he can use natural poisons as weapons without impunity.
At 11th level, not only are his armor restrictions effectively gone (via Ironwood), he becomes freaking impossible to spot nearly anywhere since he can take the form of tiny animals.
At higher levels you start getting really cool spells like the ability to summon a tornado (what Wizard spell can match the area of effect of Control Weather?), you get the Undead Nuke commonly called Sunburst, you get the full power of Elemental Swarm, and the lethal power of Creeping Doom.
18) If you play a Monk of the Sun Soul in the Forgotten Realms setting (a devotee of Lathandar, Selune or Sune), you can multiclass freely with any ONE other class so long as your Monk levels are higher than your levels in that one other class.
So you can level up interchangeably, so long as your Monk level remains higher than your Druid level to start, and once you reach the final level your want of Monkishness, say 7th, you can abandon it and go pure Druid for the rest of the levels.
Bear in mind that you could start as Druid and get to say, 5th, then go Monk to 7th, then back to Druid no matter what Order or game-world you select.
19) Small and larger animals have a normal threat range of 5 ft., so Small 1 HD Dogs might be the way to go if you want them to be able to flank and attack without provoking attacks of opportunity. So even checking out the superior damage / attacks of a Badger or Cat or the notion of having a 4th level Druid with 16 Ravens or Rats swarming her enemies, bear in mind that the size does indeed matter...
20) All I can say is a halfling with PBS and then rapid shot at level 3. This way when you get 2 level 3 you use produce flames starts of with 2 ranged touch attack with a range of 120ft. They both have +7 to hit asuming max dex and each dealing 1d4+1. Then 2 add to the fun take a ridding dog as your companion so that you can be ridding around while doing it
21) Expertise is a great feat, and I'd suggest taking it. But don't bother with improved disarm - heat metal and warp wood can easily make your opponents weapons useless (use these spells against those pesky casters with wands). Improved trip on the other hand, will be invaluable in animal form. At higher levels, you'll have stronger, bigger animal forms - trips require a strength check, and for every size category larger then medium you are, you gain a +4 bonus for tripping. if you miss the trip check, your opponent immediately can attempt to trip you, but you'll gain a +4 stability bonus for having 4 legs.
22) Cast Endure Elements: Fire, then cast a flaming sphere centered upon yourself. Then wildshape and charge- who's going to try standing up to an angry flaming brown bear?
Cast Entangle, then wildshape into a vicious flying bird of prey. You'll attack freely while they struggle with the vines.
23) Spell Casting Prodigy Feat (Forgotten Realms) would be great for a Druid.
24) If 1 Lv Monk you can pick up some nice skills you won't have class access to as a druid. 4 ranks in Tumble, Hide and Move Silent are very sweet for a wildshaping druid, and it's not overly expensive to raise Tumble to 5 ranks later for the fight defensive bonus(es).
25) A fun possibility is 2 go a halfling druid with a riding dog. Have a high dex and then one you get 2 3rd level use produce flame as your offensive weapon of choice. If you want 2 make it even more fun add PBS and Rapid Shot and Empower Spell. Then at level 8 you get 2 move 40ft and throw 3 balls of flame at a maxed ranged tough attack of +14/+14/+5 each dealing 1d4+4*1.5.
26) One combination that you can use is obscuring mist & ghost sound. If you stand still, there is almost no chance that your opponent will not go after the fake sound.
Your wolf can scent the opponent.
27) Weapon Finesse with unarmed weapons not only will improve your unarmed combat (nice when you are using shapechange) but will improve your chance to hit with a touch attack spell as well. Persistent spell is nice at higher levels (useful with stuff like Barkskin which, as Persistent, will give you a minimum of +4 (or is it +5?)to AC which will stack with anything).
As a scout/assassin, Cosmopolitan with the hide skill is useful (combined with the first level spell Camaflauge, you are just about impossible to see). Tracking is nice. (if you plan on going the scout/assassin route, be sure to take the skill Craft Poison - which is especially good at high levels if you focus on organic poisons).
28) As a spellcaster, Scribe scrolls is rather important. Miscellaneous item creation is nice at higher levels.
29) For Skill points... to make sure concentration is maxed. take craft (woodworking) and build your own and latter wood armor to cast Ironwood
30) Craft Wonderous Item is probably the one you'll want, since with that you can make necklaces, which almost any wild form can use. I like changing into apes, since you could argue that they can use rings and spell trigger items. And they can use weapons because they have thumbs.
31) For equipment go Hide armour (decent protection and its weight is not an issue because you're Small, you can carry 25 lbs before being affected and Small hide armour only weighs 12.5 lbs), and Rhino Hide at higher levels is pretty cool.
32) Rangers and Quarterstaves: Miffed because your ranger can't use his ambidexterity and two-weapon style class abilities with a quarterstaff because it's counted as a "double-weapon"? WotC's Sean Reynolds went all out for you: From [PHB author] Jonathan [Tweet]: feel free to let the ranger use the quarterstaff as a double weapon with virtual feats. [This also means a Druid with one level of Ranger could use a quarterstaff as a double weapon, cast shillelagh on each end, and spikes, and have a massive double weapon going. I wonder how much it would cost to make the shillelagh's permenant?)
33) Th Bear's Heart spell is very good.
34) Spikes: Turns a wooden weapon into a +2 enchanted weapon dealing +level damage, with a crit range of 19-20/x2. Lasts one hour per level. At ninth, an Extended-Extended Spikes lasts all day. At 12th a simple extended Spikes lasts all day. PS: From Tome and Blood.
35) Gnomes, you have the opportunity to speak with burrowing animals and their low-light vision doesn't hurt. Being small adds a nice bonus to your AC, too.
36) Quicken is another must for shillelagh.
37) Soften Earth and Stone has the potential to be your most deadly damage-dealing spell at low levels. If you are adventuring in a natural cavern, and you have opponants in the middle of the cavern, you can cast it on the ceiling of the cave, and this will this causes a moderate collapse (cave-in) as the loosened material peels away from the roof and fall. Anyone/Anything in the bury zone of such a cave-in suffers 8d6 damage, half with a reflex save (DC 15), and are pinned. Anyone/Anything in the slide zone sustains 3d6 points of damage, or none if they make their save, and are pinned if they fail their save. Pinned people take 1d6 subdual damage per minute, and start taking 1d6 damage per minute of normal damage once they go unconcious unless they make a Con save (DC 15). Collapse info is from DMG pg. 114. Even if the circumstances are not right to create such a cave-in, the spell has other obvious uses in its description that make it quite a useful spell to have prepared.
