My hair is very thin, how can I get thicker hair??

You can't really get thicker hair, it's all in your genetics... did either of your parents have thin hair, or grandparents?

You can try seeing a trichologist to see if there are any medical reasons your hair is thin but odds are you just have thin hair.

You can get your hair cut to appear thicker though, I always get mine razor cut and done in many many layers so it gives it more body and the appearance of their being more hair.