Spawns: Best way to get an enemy if none are around is to go next to the exit of the nearest box spawn and wait outside of it.
M249 - Powerful weapon, but heavy recoil. Aim for upper body, so that you can potentially get a headshot.
Saiga 12 - Get close, its an automatic shotgun
M4 - Nothing special
AK47 - Nothing special
AUG - Aim for the head, and constantly press the trigger as its a burst rifle
M16 - Same as AUG
Famas - Be gentle with your ammo. If you cannot kill your enemy, quickly reload via trigger release.
ADA 9mm - Be gentle with ammo, and aim for head.
P90 - Aim for body. Very difficult to headshot. Incredible recoil.
UMP - Be careful with ammo
PP-Bizon - Aim for head
MP5 - Try for body, headshot if going for extreme times (sub 2 min)
Mini Uzi - Shoot with two hands if enemy is in front of you, shoot with one hand controlling recoil if enemy is behind you.
Kriss Vector - Be EXTREMELY CAREFUL with your ammo. Only holds 20 bullets and fires quickly. Aim for body.
Barrett M99 - (Beginner) Don't go for range, look for someone nearby or wait for a spawn (Sub 2) Try and shoot someone far away if no one is nearby.
Modern Hunting Rifle - Go for range
AWP G3 - Go for range
SCAR - Go for range and headshots if nearby
SPAS-12 - Nothing special
M590 - Constantly be pumping with your arm so when shooting you quickly reload
Sawed-Off Double Barrel Shotgun - Go next to an enemy and shoot them in a head. Do not risk it.
Desert Eagle - Minor range is okay, but this has major recoil. Aim for upper body.
Revolver - Same as Desert Eagle
Five-Seven - (Beginner) Aim for headshots (Sub 2) Shoot the body very fast.
TEC-9 - Same as Five-Seven
M9 - Same as TEC-9
Glock - Reload before firing a single shot. Aim for head if the enemy is not damaged at all. Aim for body if they are damaged in any way.
M1911 - Same as M9
Knife - (Beginner) Run up to an enemy and stab them (Sub 2) Throw a knife if there is no enemy right next to you.