How do I tell this guy I like him?

I've known this guy for like 3 months at least maybe 4. he's in my homeroom and in one of my cles, which i sit next to him in. when our cl goes for walks we talk and in that one cl we talk a little. My parents don't approve of him, my friends don't approve of him and I hate his friends. My friends don't approve of him because he does drugs and is retarded enough to bring it to school. How do I tell him I really really really like him? I think he knows cuz some kid was like OMG DO YOU LIKE HIM?? when he was sitting right next to me and i said no twice but there were 2 ppl who knew already there and they laughed... and that person said he was flirting back soo.. yeah idk. what should i do??