I think sticking to things I start has contributed the most personal growth for me. I think for anything to have any effect on you, you have to stick with it for at least 6 months or more (though it definitely depends on each activity).

In the last 2 years I have been able to lose 8kgs, increase my business, cure my chronic backache and become a lot happier using this one trick of sticking to things daily without fail.

One thing that has helped me tremendously to keep at it daily is a simple Google Sheet in which I put my progress daily and it gives me a "X days streak" using a formula (let me know if you want the template). After a month when I have a 30 day streak it makes me more and more committed to follow through and I rarely break my streaks.

P.S. The only thing which this never worked is sleeping at 10 <strike>a.m</strike>p.m. Can't even get a 2 day streak. I guess nothing works for that :D