How to approach a girl without coming off as weird. Save Me Now!

I am a sophomore in high school, and not really that popular but know people here and there but don't really talk to them (yes it's a run-on sentence =). I have many friends who are all like in college and that and they tell me that I should just go up to a girl and start up a conversation because apparently they said high school girls are pretty easy and they regret not doing it as much in high school. And me as a thinker, I always think of what would happen because as we know rumors spread in high school in a blink of an eye. So how do I approach a girl in high school (she is probably popular and I'm not so popular) without coming off as weird. Girls of Reddit, if a guy came up to you to start up a conversation would you think of it as weird? Save Me Reddit! Lol

I am trying to also talk to girls that are not in my classes. So like after school before or after my basketball practice/game.