I think creating a ritual is important. So far in my life, the hardest thing to do consistently has been exercise. I try to go running 3 times a week, but really that's more of an ideal since something usually comes up to mess with my schedule. To get back into "the groove" I just keep my mind focused on the "high" you feel from exhaustion after a hard work out. I guilt myself by imagining me as a fat lazy blob who sits at his computer all day never leaving his basement apartment. But occasionally there are stretches of time where I am able to make it a ritual to get up at 7:00 am every other morning and go running before the sun gets too hot, and during those times it's never a question of "do I want to run today" because I just do it. I remember how great I felt two days ago and it's easy to do it again.