Crouch when you fire and aim for the head is pretty much all i can give to you for advice.
I'll tell you why these two pieces of advice are contradictory. People generally aim at the upper torso so that the recoil carries up and to the head. This goes for any CS game, not just GO. So what happens when you crouch?
The crosshair is right on your head and you're forgeted. The only times you should EVER crouch are to get into a vent or to stabilize spraying
when the enemy isn't facing you.Also don't use SMG's.
Do you even play this game? The P90 is one of the most imbalanced weapons in the game right now in terms of power and recoil. If you're trying to use SMGs from a distance greater than Ramp to DD on dust2, you're doing something wrong. SMGs are generally cost efficient for power and low-to-mid range accuracy, and while people generally don't use them farther than earlier or eco rounds, they're far from useless.
If you're only playing on auto-$16k pubs then yeah, that statement generally stands.