How should I go about getting her to be my girl?

Thank you for clicking on my question and taking the time, now let me explain :)

I am in high school, and there is a girl in my music class I've known for about a year. We were always friends in class always sitting next to each other and joking around, but only recently after our class went away to music camp, I really grew to be attracted to her. She seemed a bit more friendly to me since then, but I'm still not so sure if she feels the same way about me.

What I've noticed is she seems a bit shy talking to me when her friends (who are girls) are around. and some days she seems quite friendly to me (like touching my arm, leaning against my shoulder etc) , and other days maybe a bit distant.

I've been in a similar situation before, and actually asked the girl out, but had the complete opposite effect of what I was aiming for, and we haven't spoken since, because me showing my feelings for her made her feel too uncomfortable.

I was thinking of just sitting back and waiting for her to make a move, but I don't think she will. I think it's me who has to do it, but my question is how? I really really like this girl, she's a really good friend and a beautiful person, and I don't wanna mess this up like last time. How do i hint to her I wanna be her bf? btw she's not too princessy, she likes her sports and stuff lol

This is not my element (asking girls out) and i tend to stuff it up a bit. Does anyone have any ways that I can suggest to her, without really saying that I'd like her to be my girl, or possibly if she feels that way, to somehow let me know?

thank you very much for taking the time to read my long question. your answers are appreciated ;)