I started with having some I would eat only during work (salt sticks and peanuts), but later switched to take a treat only once after 30minutes. For that I went to my favorite chocolate - which I started to dislike after some time. For a while I actually just moved pieces around. Then i went for olives, and now i use some chocolate beans. The treat itself doesn't seam to matter that much to me, but the ritual does. Ask me again in a year. The marshmallow experiment indicates that the kid that waits does better in life, so i wanna be that kid. But you have to figure out on your own, what works for you.