There are just a few things you need to do:

first: last hit with your Q with this you can get multiple minions in 1 time (1 tip do it with low life minions or else you waste your mana which is at the beginning not that much so be careful)

second: When you are in a chase behind a faster moving enemy make sure you drop your E right in front of him so you can do Q and move to his location doing damage and lift him up in the air so he can't move.

third: This one is quite familiar use your ultimate when their attacking your turret this will capture your enemy for 3.5 seconds at least and will do a certain amount of damage (depends on R upgrade) the enemy is going to attack you so the turret will mostly defend you and will do damage. At late game this tactic wont work that well anymore because everybody has items which will support more life and armor.