This means that a person can change his bad habits and manners into good ones. This can be achieved by taking the following steps:
1. To ask Allah sincerely and frequently to help you.
2. To remember the bad habits upon doing the bad deed. For example, when you are angry, remember the bad habit of raising your voice, and when eating, remember the prohibition of eating with the left hand, and so forth.
3. Sometimes you may forget your endeavors and lapse into your old bad habits. So do not be despair, but try again. Allah will surely help you.
4. You might wish to speak with others who used to suffer from the same bad habits and benefit from their experiences. They can tell you how they managed to overcome their problems.
5. I advise you to read books and listen to recorded lectures that discuss the problem you are trying to overcome. This often proves helpful. Here is one great book about quittting bad habits : “The Willpower Instinct”
you can find it here: http://www.ebook3000.com/The-Willpower-Instinct_163606.html
Allah says: “O you who believe! Seek help in patience and prayer. Indeed Allah is with those who are patient.” [Sûrah al-Baqarah: 153]