Class
Take a class with a qualified instructor. When I was first trying to roll, I had someone who could roll try to teach me, but he did an incredibly poor job and it just ended up confusing me.
I eventually learned on my own using videos. The Kayak Roll video has a nice progression breakdown in it, and Dubside’s new video is fantastic in showing the rolls that can be done and showing that you can roll any kayak.
But lessons with a qualified and patient instructor is the way to go.