Get Numbus strike first as it is a good way to attack multiple minions while adding in an attack speed bonus. Your second skill will vary with the champion(s) you're facing off against, and your play style. I tend to go with Crushing Blow as it is a great harass combo with nimbus strike, however if you're against a pokey champion, then I suggest you get Decoy in order to trick your opponents after your nimbus strike. Afterwards I max out crushing blow first since it's a heavy damage dealer and I am adept to using my q ability right after my e with Wukong. Decoy is really only useful when escaping, but also if you engage it can trick enemies for a couple seconds and you make them waste cds on your clone. Aside from abilities, this item build is great for Xin Zhao as well, just putting it out there.

Everything should be straight forward for the item build. But until you get to really late game when you are finished the builds up to the BT, then you can go for that or you can go for a warmogs to compensate for your relatively low hp count.

I like to use Exhaust and Flash since Wukong doesn't have an ordinary skill cc, only his ult. Unless you're going to jungle and get red buff, you should go for Exhaust. Flash is for escape since not everyone is a pro Wukong juker ;)