Tiny Habits.com is my all-time favorite habit building tool, created by B.J. Fogg, PhD of Stanford University.
BJ studies how to change habits. and over the course of his decades of research B.J. has come up with the Tiny Habits system. The idea is quite simple: smaller habits are easier to build and sustain than big habits. Habit building is a skill that can be improved. When people aim to change small habits they are much more likely to continue building the skill of habitual change and thus make bigger changes in their lives.
In the last year I have used Tiny Habits half a dozen times to encourage myself to do projects ranging from handstands to monitoring my finances. Tiny Habits is free, lasts for 5 days, and has allowed me to adopts several habits that I will use for the rest of my life. Even more exciting, though, are some of the aspects of building habits that I have gleaned from Tiny Habits and begun to apply elsewhere.