You repeatebly tap A as you're falling to deploy a 'chute.
EDIT: Ninja'd, so I'll just say my favorite guns and how they can be used effectively.
Assault: Either the XM8 or the F2000, F2000 rocks in CQC, XM8 more so as an effective simpel assault rifle for mid range. Always burst fire. Unless you're within touching distance of a single enemy with the F2000, then let rip!
Engineer: SCAR-L with ACOG x4 scope, and the M2 Carl Gustav Rocket Launcher. SCAR is pretty accurate, but burst firing is advisable, but at mid ranges you can get away with sustained fire sometimes.
Medic: M249, great sights, accurate, and a fucking huge mag. Shoot however you want, you'll take a loooong time to run out of ammo. It feels really satisfying laying down suppresive support fire with it, too.
Recon: Either T-88 for long range anti-infantry, or VSS with ACOG x4 as a battle rifle for mid-close range. It seems like the VSS was made for that. It shoots fast, and loses accuracy quick with sustained fire, so shoot it by tapping the trigger, it should come out as burst of two-three shots.
Everything else:
M93R Pistol: I love this, it's so fun to shoot, and it's... alright, stat wise. MP-443 Gratch is my real recomendation sidearm, though. M93R Still looks fantastic as well, though, if you want gun eye-candy.
Saiga Shotgun: Awesome, semi auto, good range and a big mag, so go overboard with it. Very good gun. Haven't unlocked Slugs yet, so I can't tell about that.