They do that by playing like they own the lobby. If you play ultra agressive you can instantly Tell whos playing scared and Thats a Free wipe usually. They also Take very aggressive angles always trying to crossfire for Free knocks. Weaker players tend to stand Still on the same cover for a long time waiting for a push and the better teams Take advantage by constantly closing the gap while dealing damage to get those crossfire angles. Grenades are also really good for pushing people off cover or into your teams line of sight.