stop biting nails

I tried to stop biting my nails, really I did, but when I get nervous and/or anixous I start doing it again. Sometimes even when my nails get a little too long or dirty I start doing the biting again. I just have too stop biting them at all.

I have been trying for years to stop biting my nails, I even tried to but those ant-nail biting stuff on them, but I ended up liking the bitter taste. I even tries putting nail polish on them, it worked for a little bit but then it started chipping off so I would end up peeling the polish off.