One of the things that have helped my friend is getting her the best manicure and trying not to ruin it.. Plus thinking about all the bacteria in your fingernails might make you grossed out enough to stop.
One thing I do to stop me from picking the skin off around my nails is to chew gum and find something to fidget with like a tag or your drawstrings.
First of all tie an wooden tubes to ur fingers which act as insulators n on that tie electric wire on wch the other end is plugged to a switch wch always make u reminded dat u shldn't bite ur nails...
N actually I'm sorry I knw I shldnt say dis bt it's actually said that the people who bite their nails are intelligent but u shld say that "I'll nt bite my nails" b4 going to bed n whn u get up from the bed so that it is recorded in ur subconscious mind... I hope u'll forgive me for that sentence stated by me in above lines n practice this I hope u'll b helpfull hoping so u won't mind that..... Sorry once again.