Okay.
I've won lane in almost every top lane Irelia game I've played on this account so far this season:
http://na.op.gg/summoner/userName=farming%20wolves
At this elo (lol silver), I just stomp almost every top laner. I know how to trade properly. I know when I have kill potential. I understand more than the average silver player about minion manipulation. I try to time my backs to be most advantageous. There is a LOT more I can learn. Honestly, if I put in another 100 games, I'd probably be mid-gold without improving at all. It's just a matter of volume.
Anyway, I wish I had this last game recorded. I absolutely crushed my lane opponenet (Riven). I was 5/1 (died to a Nidalee gank but was able to kill Nidalee as they dove me) and well ahead on CS. Every time she came to lane, I jumped on her face and chunked her down so that I had kill potential when my CD's came back up.
I took Ignite instead of TP this game and after the 15-20 minute mark, I just didn't know what to do to help end the game. I roamed mid once or twice and later I died a couple times to poor attempts to dive while they had a Lissandra ult up. Those times I died were bad decisions and I understand why they were bad.
I guess the question is:
What are the steps to take to win a game after you've crushed top lane for 15-20 minutes and you are 3 levels higher and at least 1 item ahead of everyone else in the game?
*edit* In before "lol don't play any other lanes or champs"