I've read the book The Power of Habit and found it enlightening, but the bits I'm having most trouble with are choosing rewards and getting started. The part about choosing rewards is, by far, the most difficult for me. Everybody keeps saying "make sure to reward yourself after doing the thing you want to make habitual" but nobody provides actual examples of rewards that work and are not harmful (no, I don't want to…
However, I always congratulated myself (outloud, by name) when giving myself the treat, and pretty soon, the congratulating myself was conditioned as a reward for the activity, letting me drop (most of) the usage of actual treats.
Just treat yourself like a particularly stubborn and clever dog/cat/animal you're trying to train -- if marketing has taught us anything, it's that cheap psychology tricks work.