You’re going to fast then, I’d say. Keep the treats coming for a while still. And when you do start to lower the frequency of treats, don’t cut back in an “orderly” way, because they pick up on that very fast. He knows when he’s had a treat there will be two tricks he must do before he gets another treat, and that’s not motivational. So keep giving treats randomly. and keep a variety of treats of hand so he never know what he’s going to get. If he knows he has a chance of getting sth extra-extra yummy, he’ll work harder. And when you use a clicker, don’t say “good boy” or anything else until after you’ve clicked and given the treat. That’s a bit hard in the beginning because you have this impulse to praise right away, but it works better if you click, reward, then praise.
Karen Pryor has written a wonderful book about dog-training, Don’t Shoot The Dog. It’s applicable to any species, not just dogs, she used to train dolphins and other animals that will only do things if you make them want to do them. It’s available as a PDF here: http://clawbiespups.yolasite.com/resources/Don’t%20shoot%20the%20dog.pdf
I used a lot when my dog was young and we were doing lots of training. I still use the principles.
When I told you about Yohio’s response to my effort at teaching him a trick, I didn’t mean to discourage you from teaching a bunny to do tricks. I think it’s very good for them. Yohio outsmarted me though. Never underestimate a bunny =D