IN the early game try to harass with your e,q combo when you have your flow up.
E through a minion and use q instantly. E back through the minion wave and put up windwall to stop the return.
Once you get static shiv you should try to use your power spike by forcing your lane opponent out and roam. Roaming bottom lane is pretty easy and you can set up a good gank with ult.
Mid game teamfights
You should use your ultimate earlier in the fight. However hold it for when it hits a carry. Once you ult in, windwall and e out. Then just go back in with your team or try to get your 3rd q from minions or champions.