Kayle will have fairly easy EG farm with E,and sustain with W.Her early game damage to champions is nice,as most mages cant outduel her AA when E is active.The squishy mages will likely give you FB,and you should be able to snowball.With W and Q you can roam and snowball even more,and maybe make you get other lanes fed!

If you roamed:Other lanes should be doing well too.You can help them push and go for a high pressure.

If you won and stayed at your lane:You should have outpushed the other mid,and doing well.BUT THE GANKS ARE COMING!If you get fed and you stay at your lane you will get catched often by the jungle,so you should ward a lot,or start roaming.

If you lost the lane:You should get creeps and start buying defensive items,and wait for teamfights.

In teamfights,Ulti yourself or the ADC.Focus the enemy APC,and try to heal the one with the lowest health.Remember,you can escape with ease.