Early:
Use your q to poke the hell out of the enemy, and after you build tear you will never run into mana problems. When you get ganked, slow down the enemy and speed up your team.

Mid: Try to pressure the map with your high mobility and save as many lives in skrimishes. Positioning is absolutely key since burning ultie on yourself unless you're baiting for your team can be very bad.

Late: Peel the hell out of your adc by slowing the enemy diving and speeding up your adc so he can kite. Try to land a double stun on as many people as possible, but focus on peeling.