My startup is focused on building habits and we've found that doing one thing daily is extremely effective. In terms of forcing yourself, we decided to use peer pressure. The user chooses a few people that we can notify if the user doesn't do their daily step. These people then reply back with positive advice/feedback to the user if the user fails to do their daily step.

I created a custom goal called "Do 10 Pushups a Day" and it's been pretty good at making me actually do the pushups.

We launched recently and we'd love to hear your feedback. Link: http://www.goalhawk.com