Advice Needed Habit of biting Finger Nails.

Okay, i have this habit of biting my finger nails.
And ironically the hardesthabit for me to break.
I'm the type of person thatbite my finger nails specially during i'm watching tv shows, movies, anime ,sometimes whenever i'm nervous or just waiting someone.
I stop biting my finger nails once there isa draw blood or i feel a little pain from biting it.

I know nail biting is a pretty common thing, but does anyone else have it to this extent?
I have this habit since the age of 9 and no idea how to broke to this habit. ;-;

I ask a user that have the same habit and how she broke from itbut her method seems hard for me.
I keep restraining myself but in the end , i end-up doing it. :c