One way you can develop more discipline is to use challenges. This makes it more like a game and less like a chore. Also, there can be the element of competition with others, and having others help hold you accountable improves your odds of success.
Challenges are very popular and you can find them in many places. Or you can make up your own and share it with a group of people. You also can make your own challenge or use one from someone else to just challenge yourself. However, you end up doing it is up to you.