Shooting should always be fairly careful point-and-click unless you're within 10 feet of the enemy, there's no better way to explain that. In Battlefield especially, you only need a few bullets to take somebody out, so your eyes should be peeled all of the time for those little blips in the distance. Unique to long range games like Red Orchestra and BF is the enemy who is a mile away, has no idea where you are, and thus can't really fight back (whereas in a game like CS, half the enemies are "encountered" in fairly close quarters while the others are ambushed in close quarters). Take your time and pick them off with careful SINGLE shots. The days of accurate spray ended long ago. It can be intimidating when the enemy is pouring bullets at you, but just keep in mind that you only need 2-3 out of your 30 to hit in order to kill him. One of the most unnerving things for a person's aim and decision making skills as well is taking damage. A lot of the time when people take a bullet, and they see that flash of red and the movement lag, they just start panicking. Don't be one of those people. Create those people.
One of the most important things though, especially in the more tactical FPS games, is not how you shoot. It's how you move. In any situation, you need to be attentive to surroundings and the flow of combat and you need to move accordingly. If all you do is see an explosion, and then run straight down the road to find what's up there, some guy waiting in a window is going to shoot your dumb self. Instead, think of yourself as in a war zone (because you are) and move as much as you can from cover-to-cover, making each interval out of cover as short as possible (that's what sprinting is really for) and observing your surroundings at each covered location. That'll raise your survival ratings exponentially. Open ground engagements are exactly where you DON'T want to be, as even if you ARE good, you should always die if you're fighting more than one enemy. In the event that you're caught in one, the only advice I can give is this: sprint into the nearest cover. If that isn't at all available, drop prone to minimize yourself as a target and plug him with careful shots. Little jerky strafe techniques work too, but mostly in CS and DoD as opposed to games like BF where your run is relatively slowed. Something important to remember about the majority of FPS games with "realistic" recoil systems is that you should never move and shoot if you intend to hit any decently distant target. Even if you want to strafe about and such, when you do decide to fire, MAKE SURE YOU ARE COMPLETELY STILL.
This also increases how stealthy you are. If you're always shooting from cover, you're less likely to be seen. I think it'd be accurate to say that 90% of my kills in BF2 are on people who aren't shooting back, who have no idea where I am. If you're being shot at, at most junctures it's actually better to retreat and lure him into a situation where he's going to walk into your gunsights. If you go into a "peeking" war, there's a good chance you'll simply walk into HIS sights (especially if he shot first, since it means he has the time advantage of knowing exactly where you are.)
Eventually it all just becomes intuitive, along with reading the flow of battle and enemy positionings. A good FPS player isn't just a guy who's conditioned to twitch and fire at people's heads very quickly. That certainly helps, but tactical thinking really makes or breaks the whole deal, ESPECIALLY in a Battlefield game (where most kills are hardly twitch-related at all) but also in closer, more arcadey games like CS.
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