In order to understand this guide better, here are the explanations for the terms used in this guide.

Items
mh, mega = mega health (+100hp)
mk = medkit (restores hp up to 124hp, does not work if holder has over 124hp)
ya = yellow armour (+50a)
ra = red armour (+100a)
hp = hit/health points
a = armour
rl = rocket launcher
gl = grenade launcher
rg = rail gun
lg, shaft = lightning gun
gl = grenade launcher
pg = plasma gun
mg = machine gun
sg = shotgun
nades = grenades
quad = quad damage
regen = regeneration

Other
fc = flag carrier
efc = enemy flag carrier
pu = powerup
att = attacker
def = defender
mid = midfielder
stack = having hp and/or armour above the default value (124hp 0a)
high = the high routes that lead to your/enemy base
low = the low routes that lead to your/enemy base
mid = center of the map (usually location of powerup spawns)