Why you're still bronze and bringing down your team mates.

aim for at least 225 cs at 30 min (300 would be the best) Don't die, if you are going to try not to die more than 5 times the entire game. Don't dive turrets unless you have a long ranged move that can snipe them. Don't over extend early, don't be level 3 and at the enemy turret. (its just asking for a gank)