How To Win Games

I recently heard that to win games when you win lane, you need to shut down other fed champs on the other lane. I win my lane 99% of the time with Olaf, but I find myself doing nothing late game. It might be because of my build or that I don't shut down the fed enemies. Also, I don't know if Olaf is the best champ to shut down fed champs as he doesn't snowball much and can get kited easily. I was wondering how to start a bigger threat and having a bigger impact later in the game and in teamfights.