Making friends in High school ?

Im not loser and not super popular, i would rate me as B lister. I have a friends but none of them are in my cles. I find it hard sometimes to talk to people i don't know because i dont want to offend them with my crude humor or just bore the to death, or come off as creepy. What are good conversation starters and how do you know if a girl like you or just wants to friends. Its the 3rd day of highschool so i hope that helps. Also, i have video production as one of my cles and there is noting but weird or ghetto people in that cl how do i get through that cl( there is a couple normal people though). And How do you get through a cl with nothing but girls and all the guys are nerds i dont want to come off as gay if i join in a conversation about a clothing store just because that is the only thing to talk about.