It helps to first try to understand the habit. What benefits does it provide? Why do you do it in the first place? We can list pros and cons all day but one side will always win out over the other generally, the side that requires no effort on our part.
Why do you want to break the habit? Is it your idea or someone else's? Is it because you "should" quit or because you "want" to quit? Attitude is everything. Quitting is difficult, if not impossible, if done for the wrong reasons. This is because the wrong reasons are unconvincing to you. It does not matter if the entire world thinks you should quit; your opinion is the only one that counts.
Therefore, if you truly want to quit, you must change your feelings about the habit. Think of what disgusts you about it, the things you loathe, the things that make your skin burn red in embarrassment and shame. Then imagine yourself as a happy, free, powerful person who simply does not have that noxious habit in their life. Feel the joy of being free from control. Enjoy the power. Take pride in your accomplishment Keep hold of these feelings through your quitting process and have faith that you are already becoming that better person.