Set Goals
If you see that the effort is too great, try to divide your goal into simpler stages. This method is slow and paused and focuses on achieving the goal progressively. For example, stop biting your thumbs first; when you see how good they look, this will encourage you to progressively stop biting the rest of your fingers.
Find substitutes
When you get the urge to bite your nails, look for a quick and healthy substitute. Chew gum, eat candy, drink more water… Other food products can provide the solution to a common disorder. Keeping your mouth busy at key times may help nail-biting reduction more than you think. Many people who have succeeded in eliminating this problem have done so with the help of products such as gum or candy. In short, betting on substitutes can be more than effective.