I write out the verse I am memorizing on an index card, and on the flip side I put the reference. I carry that card with me wherever I go, and if I am in a line up, I can just pull it out and go over it, starting with the reference, and flipping only if I need a hint on the verse. I did the same thing to learn Greek and Hebrew in Bible college. There, we punched holes in one corner and used a split ring to attach the (many) cards to a belt loop. It works well.