how do i start talking to him?

So if 당신 saw my 이전 entry, "does he like me... 또는 not?", 당신 probably said he does indeed like me. If 당신 haven't read it yet, then 당신 should probably go and check it out so everything makes 더 많이 sense.

Two people commented saying that they assumed he liked me and I should try talking to him. Thing is... I don't necessarily know where to start. It's not like I'm a complete stranger to him - I've talked to him before, it's just that conversations don't go the way that I plan them too. Either we're too shy to say something else, 또는 someone barges in and takes the limelight, so he ends up talking to them and not me.
As I said before, this guy is one of the most 인기 boys in school and he's extremely musically talented. He loves playing 피아노 and preforming magic tricks. He's quite weird, actually, and he's pretty poetic. He likes 연기 and is probably one of the best singers I've ever heard for our age.
Again, I don't know what kind of topics to start talking about... I've always had this extremely high social anxiety level since I was bullied mercilessly in the past. I don't have any 프렌즈 (literally, I'm not exaggerating) and I find it hard to make friends. Let alone talk to the guy I like! So what can I do to start a conversation with him?