I love rolling the bottom of my jeans, I always think it makes it look like I pay a little extra attention to how I wear them. The first pair on the left has a simple twice fold over roll, in this case it shows that these jeans are cut on the selvedge which makes them special. The middle pair has a roll that is a little less formed (it's how J. Crew does it) it's actually harder to achieve because of the unevenness of it. Yhe third on the right is a big cuff look, just make sure your jeans are long enough for this. You do not want to look like your trying to be overly young.