sneaky claymorers... they take me down without warning...
As for situational awareness from SL perspective. I have to set up the SM s to be watching every direction... And good TG players always spot incoming threats before they even fire their first shot. So it is all good and done...
When capping a flag I always look at the spawn points. And a solid communicative squads always let their mates know.
"Hey X behind you, ooh you are dead... I got your revenge."
Fun, fun and more fun. But do not be selfish. Provide some fun and you will receive some fun.
As a SL (especially on Defense), get up high. Whether it's a tower or smokestack, or roof. Stay up there and spot all incomings for your squad. Call out the nature (2 infantry) and direction (from the Northeast). Request a UAV for repeated assaults, and try to spot/ID the SL. Also pay attention to the minimap and note from which directions attack is likely. Try to note any open armor that disappears at an adjacent CP - it is probably coming toward you.
One thing I had to actively teach myself when playing as a SL: don't shoot at anything that moves. Hang back a bit, and let your squad members do the actual shooting, leaving only the odd straggler to mop up. Once you start engaging the enemy yourself, you'll tend to focus on that one target, losing SA in the process (of course, excellent squad leaders can maintain SA whilst shooting the enemy left-handed, but that's a gift only the demi-gods amongst us seem to have).
Similarly, in a jets squad, the best position for a SL might be the WSO seat in the bomber (or even not flying at all, sitting on the ground in an AA vehicle or sorts). When not being constantly occupied with preventing flying your jet into all kinds of deadly objects (missles, pylons, supply crates, pine trees), you'll have a lot more time to maintain SA and direct your pilots to the right locations.
I played Engineer as squad leader and that helped SA a lot. With the shotgun you have to stay back, be patient, and not engage enemies unless you absolutely have to. You also become more skilled with the grenades and pistol. With an asuault kit its to tempting to just spray and pray, and not concentrate on the larger aspect of the battle.
Okay, these are ancient arts of chinese fighting that I learned from my Zen Master so be verrry quiet about this.
+ When assaulting, always stay around the outskirts of the battle where you don't believe anyone can get behind you.
+ Keep looking right and left, because that's where the enemy will come from, young grasshopper.
+ If inside the small sqaured area around the flag (not very close to it..just enough to see it), stay behind cover and continually move around and check for enemies. The old zen master once told me a sitting duck is a dead duck.
+ Pick a target and do your best to advance on his position through flanking. Where there is one bird, there usually will be a flock nearby.
I could give you the deeper secrets of Zen during battle, but you'll have to pay a flat rate of $19.99 an hour. Hope this all helped! =)