First off this is somewhat like a review and tips in one - though you may not agree on all of them
I've played PR for some time now and in RL I end up annoying my boss, other employees, family, friends, family's friends and so forth about how much fun PR is
I guess I should bullet these as ill probably add more.
#1: Rolling hills: People tend to sit on the very edge of a hill, at the top and engage enemies from a distance, where they take fire and get headshotted, where as sometimes its better to stay in the terrain and move around. ( Ejod Hills, Jabal Al Burg East Beach Hills, Etc )
#2: Throwing Grenades: Please be careful, I think the viral quote is "When the pin is pulled Mr. Grenade is not your friend"
#3: Element of Surprise: Sometimes before you fire off your itchy trigger finger think about it first - I've seen countless moments where you can silently engage an enemy, or throw a grenade onto multiple foes before you engage. Also driving directly into a hostile flag without knowledge of the situation ends up leaving you surprised - and dead.
#4: HAT Kit and Corners: I know you want to make that shot, inching out, but you have to be EXTREMELY careful with the HAT kit on edges, hills, obstacles, and around other people, because you can and WILL kill yourself and everyone around you should you hit in front of yourself at point blank.
#5: Don't Solo Please! : Common sense, but sometimes you really... really.. shouldn't run off with a vehicle alone, or even in .8 ( pre .85 ) drive off with an APC without seeing if you can transport troops.
#6: Insurgency: Sort of linked with the element of surprise, you really should take your time, be careful and conceal your movement because insurgents flock to US gunfire because... well... the secondary objective and only way to win is to kill off the US/British troops1.
#7: Communication Between Squads: Check up on other squads at flags if you are moving into the next cap zone so you don't end up out of position, or announce if your going to cap/lose a flag so people can take precautions or advances.
#8: Practice Before Takeoff: Don't go in vehicles that require limited kits without at least practicing taking off, and possibly even dropping some munitions on practice targets in a training server - personally I don't fly attack helos / jets anymore, but you shouldn't run off without knowing how to operate the 20 min spawn vehicles to a minimal degree.
#9: Audio Clues: If you can use Ultra-High sound or 3d-surround sound, DO SO, it will increase your situational awareness twofold as you will be able to pinpoint vehicle sounds ( Memorizing what they sound like makes life easy in PR as well ) Footsteps also apply, as you can guard areas like openings in fences/doorways and hear people walking - the only exception I think is crawling when prone on dirt you make little/no sound, though prone on metal surfaces I have heard teammates making a small footstep noise.
#10: The 5 meter rule: SL dropping assets - sandbags, wire, 50 cals etc. - can place a marker then back up until the marker is 5 meters to get a more accurate drop of the asset in the place you want.
#11: Chatter: BF2 Voice lowers your ingame sound, and so if the squad is engaging targets, or trying to focus on something important like orders, try and keep chatter, like "UGH I get shot every time this sucks" to a minimum.
#12: Can we get a rally point?: Sometimes it isn't the best time to be asking for a rally, as the new overrun rules make it optimal to place them FAR AWAY from enemies as if you put it close, and spawn... then engage you will just eventually bait the enemy to your rally and have to start from scratch!
#13: Second in command: Sometimes you have to step up, and when things hit the fan and your SL is dead, someone needs to take over the infantry group and give on the fly orders of what to do - assuming your SL is LONG GONE and unrevivable.
#14: Stay Awake: If your defending a flag, its generally an easy job - but enemies will strike you standing still via accurate fire, whether it be a tank that crested the hill you didn't notice, someone walking inside while your busy wandering a flag aimlessly, or when you fail to guard the main entrance to a one way building.
#15: Call for backup! If your in trouble don't be afraid to use team chat ( I mean if your leading a squad or are "representing" that squad via text )
Many times I will say "This is Sq2 were at village, we have an enemy tank at the northwest road were pinned down and under attack by infantry at the south etc etc.
Some random tips I plan to add to because I can't make use of these thoughts before I go to sleep
Random thoughts..
Whats up with the sniper/marksman love for new players - especially ones who don't understand the mechanics and think it should be deadly accurate at all times?
Side Note: I'd like to thank the RDEVS, RCONS, RMODS, Server admins, and all the players who "play the game right" - PR has been an enjoyable experience for me and made BF2 - a game which I was frustrated by in vanilla initially - and turned it into a game of my dream which your trigger finger doesn't dictate skill all the time.
( .3 
PR is best what happened to me ^^ ( if speaking of games of course )