Self development is an important practice. It helps you to understand yourself better and create balance in your life.
Self development is same as trying to clean a messy room after a month! To do so, you must start small and progress further, but how?
When you're new to something, you're told you "Observe and Report!". Same works for self development. You're supposed to reflect and improve what you find messed up about/within yourself. If you can't find the problem, you can't come up with a solution.
There's a hadith that states,
An hour of reflection is better than an entire year's worship
Before you go to sleep, think of all the things that you did that day, like replaying a movie of the entire day in your mind. What wrongs did you do and what rights did you do? Were you rude to someone or let out your anger on someone? Did you miss prayers? Were you selfish? Did you insult someone? Did you get into a fight? Perhaps someone got hurt because of you? You get the point.
Pick one and decide not to do it for one day. You could start with, I'll not be angry with anyone for the entire day. Go through it for one day and then increase the number of days to three and so on. Once you go through it for a month, move to the next bad habit.
It'll take time but it'll be worth it. One year and you'll be a completely different person; a person with a balanced and sound mind. (Unless your list is too long :3 )