This article is about what to do or not to do when pinrolling jeans. Before you consider all of that, you need to know how to pinroll your jeans in the first place. Start by having your pants uncuffed. You're going to want to grab the inner inseam of your jeans, pinching it, and pulling it out. You're then going to fold it in, and grab the bottom of the pant where the fabric now overlaps. Cuff your jeans up once, while still holding close to that overlap. For the second cuff, make sure you tuck that overlap all the way in. Smooth out your cuff, and you're good to go.
If you're a visual learner, watch this video below: