if you're in high school and you want to work on your game your best bet is to just find a mall/pool/beach/park/shopping area nearby with other HS girls your age that you wont see on a regular basis. if you can find this just get your approaches in here and figure it out intuitively. don't think too much about these approaches just do it and you'll naturally figure it out, get their snaps/numbers and try to hook up with these girls. hell if you look old enough you could even try a local college/community college.
for girls at your school just flirt with ones in class or that you see casually. follow the law of least effort, you don't want to seem tryhard. but develop a friendly/flirty vibe and eventually ask them to hang outside of school when the vibe is right.
but main advice if your anything like most HS guys (me included) at that age is don't be ashamed of your sexuality, be confident and own it. you don't need to worry about your reputation because flirting with girls in a callibrated way is a complement. don't be afraid to call girls cute to your guy friends or to girls when your talking to them and be
sincere with it. some of your friends/other guys might be weird about it. don't be afraid to lower your standards a bit, especially if you are still a virgin as getting past that hurdle and getting a few sexual experiences under your belt at a young age can really boost your confidence with girls and make things a lot easier going forward. A lot of the guys who started dating early in my HS with sometimes questionable girls ended up dating some of the cutest girls later on because they had experience and weren't phased by shit the way unexperienced guys are.
but
dont read too much pick up shit right now honestly. you should understand moving fast (
https://www.girlschase.com/content/secrets-getting-girls-move-faster), law of least effort (
https://www.girlschase.com/content/law-least-effort), and how to not hide the banana when talking to girls, referincing this article here (
https://www.girlschase.com/content/how-use-indirect-game-get-girls), and maybe the girls are cute and silly article (
https://www.girlschase.com/content/girls-silly-and-cute). anything much more than that is just gonna cause you to procrastinate, act weird and overthink shit (not because the information is bad but since you dont yet have the real life experiences)
hooking up with classmates in HS or other girls your age should be
easy. when you get older you'll look back at how many cute girls were just waiting for any decently cool guy to show them a good time, there is literally no competition. id be happy to answer any more questions if you found this helpful at all. cheers.