1. Think of an area you need to work on and take on one aspect of that area that you will try to do 100%.
For example, if you feel you need to work on tznius, start making sure that your knees are covered whenever you are sitting.
2. Make sure you go to some kind of shiur at least once a week.
3. Hang around people who are the type of people whom you want to emulate, and try to become friends with them.
4. Don’t hang around people whom you don’t want to emulate.