1. Make sure you check the intensity of your problem before starting the EFT and also check it after the session is finished. You need to get it to a zero before continuing or finishing.
2. Check several issues of why you might bite your nails. Eg: because I am bored, because I am anxious, because I am nervous. Try and find out exactly why you bite your nails and then do an EFT session on it.
3. Rub you cuticles ands just below your nails with some warm olive oil every day. It will stimulate the blood flow to your nails to help build healthy strong nails.
4. Tapping your nails on a table gently will also strengthen your nails.
5. If you have been biting your nails for a while you may find the nails split as they grow. This in itself might make it tempting for you to start biting them again. If this happens, do the EFT on that.
6. Continue to do EFT until you have completely got control over not biting your nails.