There is actually a lot more to my answer than this, but I don't have time for a full reply.
TACTICS (INT; TRAINED ONLY)
Tactics is the skill, knowledge, and understanding of how to fight and particularly how to work with others in battle. Tactics are used to direct the movement of troops in battle, to correctly assess the tactical value of terrain, and to move in battle formation.
Check: Close Formation (DC 10): Three medium sized creatures can engage in melee along a 10’ wide front without squeezing penalties, provided that all three succeed in this check. If any of the creatures are size small, all gain a +2 circumstance bonus on this check. If all the creatures are size small, they all gain a +4 circumstance bonus.
Phalanx (DC 10): If you use a range weapon to attack an opponent on the other side of an ally, the opponent does not gain partial cover from the ally provided both you and the ally make this check.
Assess Opponent (DC 10): As a free action, you can gain a single piece of information about an opponent who is engaged in combat – whether or not they have a particular feat, advantage, or disadvantage, whether or not they have an available attack of opportunity, or what stance they are currently fighting in (aggressive, defensive, full defense, or normal). You may ask only one question per round of combat, and you will only receive a ‘Yes’ or ‘No’ response.
Assess Terrain (DC 15): As a free action, you can gain full details about the terrain of any 5’ square you can observe clearly. For example, you will know the balance DC of passing through the square, whether it is difficult terrain, what degree of cover or concealment it provides, and whether it offers in circumstance bonuses or penalties to combat with respect to other squares. If you make this check as a full round action, you gain similar information about every 5’ square you can clearly observe, allowing you to receive answers to questions like: “Where can I find the best cover/concealment?” or “What is the least exposed route across the stream?”
Fight in Ranks (DC 15): If you have a range weapon, and an adjacent ally is directly between you and your target, then you may treat your attack as if it originated from your ally’s square, provided both you and the ally succeed in this check.
Form a Shield Wall (DC 15): You may add your base shield bonus to the base shield bonus of any adjacent ally, provided that they have a shield, are not flanked, and succeed in this check as well.
Improve Cover (DC 20): If you have cover, you may at your option treat it as one higher step of cover.
Prevent Flanking (DC 20): As long as you are not also flanked, you can negate the flanking penalty against any single adjacent ally.
Tight Formation (DC 25): Two medium sized characters can engage in melee along a 5’ wide front without squeezing penalties, provided that both succeed in this check. If either of the creatures are size small, they gain a +2 circumstance bonus on the check. If both of the creatures are size small, they both gain a +4 circumstance bonus on the check.
Flank from adjacent square (DC 25): For the purpose of flanking an adjacent opponent, you may consider your character to occupy any unoccupied square you are adjacent to.
Enhance Initiative (DC 25): If you were prepared at the beginning of combat, you gain a +2 bonus to your initiative.
On Guard (DC 35): If you would be surprised, you may become prepared instead of flat-footed.
Enhance Group Initiative (DC 35): If every ally was prepared at the beginning of combat, they all gain a +2 bonus to initiative provided they were under your direction.
Special: You have a +2 synergy bonus when using this skill to Assess Opponent if you have at least 5 ranks in Sense Motive. You have a +2 synergy bonus when using this skill to Assess Terrain if you have at least 5 ranks in Survival.
BATTLE COORDINATOR [GENERAL, FIGHTER]
Your advice and assistance in a battle is almost invaluable.
Prerequisite: Int 11, 5 ranks in Tactics
Benefit: Whenever you successfully aid an ally with the aid other action, you can extend the same bonus to either every ally that is adjacent to you, or every ally which is engaged with an enemy you are adjacent to (your choice). In order to be eligible to receive this bonus, the ally must be capable of communicating with you in some manner.
COMBAT INSIGHT [GENERAL, FIGHTER]
You are particularly good at seeing how you can make a difference in a fight.
Prerequisites: Int 13, base attack bonus +3, Tactics 1 rank
Benefit: Whenever you successfully take an aid other action to assist an ally in melee combat, that ally gets a +4 circumstance bonus to hit on all attacks for that round.
Normal: Whenever you successfully take an aid other action to assist an ally in combat, the ally gets a +2 circumstance bonus to hit on all attacks for that round.
COMBAT LEADERSHIP [GENERAL, FIGHTER]
You can share your tactical acumen with your allies.
Prerequisites: Tactics 4 ranks, Leadership 4 ranks, at least one eligible feat
Benefit: Once per round as a free action, with a successful DC 15 leadership check, you may grant an ally for one round a bonus feat, provided you already have the feat and it is one of the following eligible feats: chink in the armor, combat surge, expert tactician, fighting withdraw, heedless charge, hold the line, make the most of it, press the attack, stand firm, teamwork, and wait for the moment. With a successful DC 25 leadership check, you may grant a bonus feat to every ally within 30’. Each ally must receive the same bonus feat, and you may only attempt to grant feats once per round. In order to use this feat, you must be able to communicate effectively with your ally.
EVERYBODY DUCK [GENERAL]
Your skill at evasion is a benefit to others as well.
Prerequisites: Tactics 1 rank, Base Reflex Save +1
Benefit: When you must make a reflex save, if you succeed, you may also make a DC 15 Tactics check. If you succeed, all allies within 30' receive a +2 circumstance bonus on any reflex save this round which is provoked by the same attack.
HEAVY INFANTRY [GENERAL, FIGHTER]
You are trained to perform as heavy infanty.
Prerequisite: Tactics 4 Ranks, Base attack bonus +1
Benefits: You are capable of performing the following tactics.
Legionaire: When formed in a shield wall, you gain a +2 bonus on reflex saves against spells or spell-like effects, and you are treated as possessing evasion. (If exposed to any effect which allows a reflex save for half damage, on a successful save the character takes no damage.)
Professional: You can take 10 on a tactics skill checks to fight in Close Formation, Fight in Ranks, Form a Phalanx, or Form a Shield Wall regardless of distractions.
Weight of the Formation: You gain a +1 circumstance bonus to hit for each rank of heavy infantry formed up behind you, to a maximum of a +3 bonus.
IMPROVED CIRCLE [GENERAL, FIGHTER]
You are master of positioning your opponent where you desire.
Prerequisite: Int 13, Combat Expertise, Tactics 1 Rank
Benefit: You have a +2 bonus on circle maneuver checks. If you fail a circle maneuver check, you do not draw an attack of opportunity.
Normal: When you initiate a circle maneuver and fail, you draw an attack of opportunity.
MASTER TACTICIAN [GENERAL, FIGHTER]
You are adept at reacting to changing circumstances.
Prerequisite: BAB +2, Int 13, Tactics 5 Ranks
Benefit: Whenever you take the Ready action, you may ready two separate actions each with its own trigger.
SHAPE THE TERRAIN [GENERAL, FIGHTER]
You remain keenly aware of your environment even in the thick of battle.
Prerequisite: Int 13+, 4 ranks tactics
Benefit: Once per round addition to any other actions you take, you may take an extra attack action at your highest BAB, provided you only use this attack against an unattended inanimate object.
SKIRMISHER [GENERAL, FIGHTER]
You are trained to fight in the open.
Prerequisite: Dex 13, Dodge, Tactics 1 Rank, Base attack bonus +1
Benefit: Provided your armor check penalty does not exceed -2, you can use the following tactics.
Peltast: If you have a throwing weapon in hand at the beginning of a charge action, you may throw the throwing weapon as a free action before the charge at your full base attack bonus.
Pull Back: Whenever you take the withdraw action, you may move an additional 10’.
Skirmish Line: Once per round, when the opponent you designated with your dodge feat enters your threat zone, you may make a 5’ step provided this would bring you adjacent to your opponent. This movement does not provoke an attack of opportunity from the designated opponent.
SUPPORTING TACTICS [GENERAL, FIGHTER]
You make everyone around you better.
Prerequisite: Base Attack Bonus +1, Tactics 4 ranks
Benefit: Whenever you are eligible to make an attack of opportunity, you may forgo that attack and instead use aid other as an immediate action assisting any ally which is also in combat with the foe you were eligible to attack. This action counts against the number of attacks of opportunity you may make in a round, but does not count as an attack of opportunity against the foe. If the foe latter draws another attack of opportunity from you, you may respond to that opportunity either by activating the feat an additional time to aid a different ally or making a normal attack of opportunity.
TACTICAL REPOSITIONING [GENERAL, FIGHTER]
You know how to move the fight to fight on the ground you want to defend.
Prerequisite: BAB +1, 4 ranks Tactics
Benefit: When you take a 5’ step as part of a full attack action, you may choose to draw no attacks of opportunity as a result of leaving the threat zone of any of the creatures which threaten you. However, if you take this option, each opposing creature which threatens you may choose to take an immediate 5’ step so that they are closer to you, if they are capable fo doing so. These moves are made in initiative order; if one opponent is unable to make a legal move it loses the opportunity. Additionally, you may engage in a special combat maneuver. At the beginning of your turn, you may designate one of the foes that threaten you which has a clear and unobstructed path to you. If you succeed in an opposed Tactics or Disguise check (your choice) versus the target’s Tactics or Sense Motive check (their choice), that target has been tricked and MUST make a follow up move closer to you after you complete the move. That target is also treated as if it had the highest initiative order among eligible foes and moves first.
if using Oversized Shields. If the parry rules are also also used this can be a formdable defence. FI also allow fighters with multiple attcks using strbbing weaponss to use 2nd attack to actual st5rike from behind the wall at -4 penalty. 
