On top lane you have to be agressive against your opponent!Try to kill minions with your shield,to absorb incoming damage from trading.Or you can use you're Hammer Time Combo (HTC) and then pick up you're shield.The HTC is you're main combo: E to push an enemy against a wall (Stun) Q because you're most damage,and then auto (if you have passive).YOu will half you're enemy's health by this combo.Use W against champs that can dash or to catch up.
You're ult could be a game changer!Use it if they have a fed carry to push it out from the teamfight!Or you can use instantly to knock enemies up and position yourself to use HTC.You can easily make a mistake so be careful!
NEVER USE R AS A LONG RANGE EXECUTE if they even have a tiny bit of chance to survive!