I was never a consistent flosser until I discovered these babies. The double strand of floss actually captures and holds whatever gunk is hiding in your teeth. Totally gross, and totally effective in converting me into a regular flosser. Now that I know what kind of garbage is hiding between my teeth, it bothers me. At the end of the day, if I brush my teeth and skip flossing, it bugs me to know the ick that is still hanging out between my teeth. Old single-strand dental floss never revealed this, so the immediate benefits of flossing were hidden.
My most consistent good habits are those that rescue me from something that bothers me at a visceral level. It bugs me to see an unmade bed. My legs feel tight and restless if I don't walk enough. I clean the kitchen each night because it annoys me to be greeted by a dirty pile of dishes first thing in the morning.
So essentially, the healthy habit is the inverse of the annoying condition. To develop healthy habits, maybe it would help to laser-focus on the things that bother us and gives us an uneasy feeling. Really dwell on them, until we get so disgusted that we develop a habit to eradicate the condition. And then maintain the habit by constantly reminding ourselves of the terrible annoyance we'll feel if we skip it.
Three more:
How to Stick to Little Healthy Habits (Like Flossing) Without Thinking