Quitting nailbiting is just like quitting any other bad habit. It takes willpower and effort... fortunately it's not like quitting smoking, since your habit is psychological rather than physical.. . 1. Figure out when you bite your nails. Is it when you are bored? Thinking hard? Stressed out?. 2. Be conscious of those times. If you bite when you are bored, come up with something different to do with your hands and mouth during those times. Chewing gum, or writing, or needlepoint. Anything.. 3. Give yourself both positive and negative reinforcement. Say to yourself, "If I go a week without biting my nails, I will get (some small treat)". Stick to it. Likewise, if you find yourself biting, give yourself some small negative consequence (You can paint your nails with something nasty-tasting... Sally Hansen used to make a foul-flavored nailpolish just for this purpose).. 4. Set small goals. Start by not biting your thumbs or pinkies. Once you've gotten used to that, step up to more and more nails.. 5. Try making your nails noticable with a manicure or bright paint, so it is harder to absentmindedly nibble.