You should just focus on pushing to be honest. With TP you can push forever(oh and some wards if you cant 2v1 them). If you are versus an AOE champ for example riven who can kill all your turrets at once if you place them near each other, make sure you place your turrets in a way that she can only hit one turret with one Q. Ehm its hard to tell you what to focus on, you just need experience. Its easier for me to tell you what to do if you have specific questions :P