First of all. Sorry for my English. I'm not that good in it.
I made this guide for normal games with friends. I don't recommend this guide in Ranked cause people probably think you are trolling and will flame and report you.

In laning phase you just want to poke as much as possible cause most of the midlaners will outdamage you midgame. Against ranged champs you want to poke with your Q. Against melee champs you want to poke with Q and W. If you are getting poked heavily you should try to pick up your Randuins Omen/Spirit Visage as early as possible so you don't fall behind that much. If you still get poked too heavily you should ask for ganks and farm with your Q.

You just want to poke as much as possible cause most of the midlaner will outdamage you midgame. Against ranged champs you want to poke with your Q. Against melee champs you want to poke with Q and W.

When you are getting ganked you should just run back to your tower. In case of emergency use Ghost or Ult.
When your jungler is ready for a gank. Try to slow the enemy with your Q and then run into them and use W. If you and your enemy are low use E for more damage.

In teamfights you want to rush into the enemy team and do as much damage as possible against their carries. For that you activate your ult and W. If you ult is almost over you should run out of their team. In case of emergency use Ghost.