First of all you need to confront your problem. You need to capture pictures of your damaged nails and jolt down their problems.
Set a start day
Pick a day on which you won’t bite your nails. You can set a reminder on your phone or encircle it on a calendar.
In case your attempt is unsuccessful, you can pick another day to quit this habit.
Visualizing healthy nails
See your hands with strong and healthy nails. Try to get a manicure with a clear polish so you can appreciate your nails.
Paint your nails
Try painting your nails with bright colours so you can become aware of when you are biting them. You can also clear or buffer your nails so you may feel bad when biting them.
Force to protect specific nails
You need to force yourself to protect a certain nail at a time. After few days you will notice the difference between a healthy nail and the nail you’ve bitten.
Once you’ve grown a protected nail, start protecting another and carry on with this tradition. Do not ignore after they have grown well and keep on shielding them.
Eat calcium and magnesium rich foods
Start eating calcium and magnesium rich foods which will help your nails repair and grow. Also, most of the reason someone wants to bite nails is because their body is lacking calcium and magnesium.
Find some other habit for your hands
Instead of biting your nails, chose some other hobby. Some people like to twiddle their thumbs, put hands in their pockets or drum their fingers. Remember to choose a helpful one and not a bad habit.
Discourage yourself from biting nails with nibble inhibitors
Paint a nibble inhibitor to discourage yourself from biting nails. Bitrex is a chemical which taste foul and is easily available in pharmacy. Carry some with you at all time and in case it fails to discourage you, try another one.
Distract your mouth
Keep gum with you at all times. In case you feel the urge, start chewing it. You can also eat carrot sticks to distract your mouth.