You just have to keep playing. Kicking you from the game if you're not doing something terribly stupid sucks though. When you get Ranked it will get better I suppose.
Watch some basic tutorials and play against bots to get to know the maps, and perhap play some deathmatch to better your aim. After that, just keep on practising. The CS community has always been like that, just mute/don't pay attention to trolls.