When it comes to self-improvement, the reason that you change is because you come to care enough about yourself, to make it worthwhile. Inner values play a role in change. If people make behavioral changes without changing their internal values, beliefs and attitudes, the new behaviors are less likely to stick. Strong motivation, then, makes change easier. Before you do anything, you must have at least some desire to do it.
Preparation is necessary, too.
As creatures of habit, we prefer the status quo. So if there's a habit you'd like to change, get to know yourself better and understand the reasons for it. How you think, feel and act, have important consequences in your relationship with yourself and others. Because habits are so much a part of your character, knowing ways to eliminate bad ones and develop new ones, is invaluable. You can improve anything, if you persist.