Guy help and advice?

[Natalie]

Ok, this is my first question on here so don't judge

Well im 15 and I have never had a boyfriend, I have got a crush on this guy who is in some of my classes.
Well in my art class he used to come over to me and compliment me on my work, I dare say im pretty good, anyway he would just be there for a while and watch me work and I'd just make small talk about what hes doing and smile at him. But now he never comes around to me anymore.
In pe we sorta hang out a bit because im friends with some of his friends, but these are the only times we are togeather. Never see him out side of school because he doesnt live in town, and we dont hang out during lunch because he is always with a large group of guys.
What im really asking is how should I approuch him and all (I can be quiet shy and get very nervous) I suck at flirtling so help there too please and any ways I could catch his eye, like there are a lot of girls at my school and a doubt non of them would like him because hes not the most attactive guy, more srawny too, but to show im interested?

Sorry for being so long, just have a lot of questions and my friends don't really help, thank you for your time.