How do I get a girl to like me if nobody knows me and I'm not popular?

First... Pick a girl that is not popular.

Second... Say hi every time you see her.

Finally... Ask her out for some pizza.

1. Work out everyday.
   
2. Find a hobby and get really good at it, like playing guitar or gymnastics.
3. Shower often.
4. Take care of  your teeth.
5. Read books.
6. Walk around school with your head up high and smile at everyone.
   

You can't really make a girl like you. That's all I can say though, because I'm not a professional with girls.