How do I 'get' a girl?

Hey all, this is my last question/post on here before I delete Reddit.

There's a girl (16F) in my (15M) grade who I've had a crush on for about a month by now. At our school, we have six class periods, one lunch period, and 'advisement' on Fridays (making 8 periods).

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The girl (we'll call her Jane) is in 6 of my 8 class periods, including lunch, so I guess I couldn't help but crush on her. We talk almost every day and we walk together to class occasionally. We also wave and smile when we pass each other in the hallways and she'll occasionally initiate conversations. The problem is, I'm an average looking guy, taller and bigger than her, but I hardly talk to other girls and am pretty quiet when I'm not with my other friends. Our goals mostly align; we are both athletic and do very well in studies/academics. But I don't really know how to have a conversation with her beyond school stuff, where I can get to know her and she can get to know me on the personal level.

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If you all have any tips on how to improve looks in general (currently bulking and working out etc) and how I would engage/initiate in personal conversations in person and over text.

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Thanks all