Sorvahr-
I don't know if I would call myself an expert, but I am playing a Ninja now, so maybe I can share some playtesting experience. First off, I would be very cautious about focusing too much on using ranged attacks. Without the extra Sudden Strike damage, the Ninja's damage output is so low that you will get outclassed very fast in combat. It is generally harder to get Sudden Strike with ranged attacks than with melee attacks. Admittedly, staying out of melee will help your survivability with low hit points, so I can see why you would do that, but...
I use Combat Expertise/Improved Feint pretty frequently. The combo gives me an AC boost to better avoid being hit back in melee, and the Feint (as move action) sets me up for a Sudden Strike pretty reliably. That saves some uses of Ghost Step (Invisible) for when I need them. Or, I can use them in combination againt a tough opponent, so that the +2 to hit while Invisible balances out the Combat Expertise for +2 AC. All of these only work for melee attacks, of course.
For ranged attacks, I rely on Hide and/or Invisibility. I am multiclassed as Cleric with Trickery domain, so sometimes I use Invisibility instead of Ghost Step (Invisible); if you can find a way to get Invisiblity via Potion or whatever, do that. With the Sniping rules, you can snipe from hiding to get your Sudden Strike, then Hide again at -20 penalty. That is nearly impossible at low levels, but gets better at mid-levels. Remember that this only works within 30 feet, though, which is another reason not to ignore your melee skills, for when the enemy runs over to you!
Other feats that may help: Cloak Dance (Complete Psionic) gives you Concealment to Hide. That is useful when there is no Cover around. Neraph Throw (Planar Handbook) denies DEX bonus for ranged attacks. There are several sneaky feats in PHBII that will work for you.
Essentally, I would recommend literally thinking 'like a Ninja'. *ALWAYS* be trying to Hide, just as a good habit. Ask your GM about terrain and cover in every place you enter, just to keep your options clear. Good luck! It is a fun class to play.