Well its actually pretty easy.You know what to buy, how to skill, you know the masteries&runes.
now you can destroy them low diff^.^
Ghost: Well, with your Q skill you get out of every slow, means you are able to get away with ghost everytime, and even in offensive gameplay its usefull, lets take a towerdive, you run in the tower with ghost and you are way faster then every other champ, so its impossible to get away from you. So you go for a fast dive.
Exhaust: gives you a nice slow & DMG reduce(pushes your speed too cause with ghost you are hilariously fast & the enemy is slowed from your Exhaust = WIN) i mean in any situation you will get the enemy oooooor you will get away from him, and with Merkurys and your W shield even stuns wont last long.
one last thing, you have to play a bit aggressive, not too much and not too little.
(sorry if my english is bad, i tried my best^^)