If only I knew back in high school what I know now...
Anyway, school is a bit of a different beast because you tend to see the same people every day, meaning other people can be nosy and get into your business. If anything, your goals should be to (a) talk to her when you're both alone; (b) ask for her number, and (c) ask her out.
(a) talk to her when you're both alone
If you see her at her locker by herself, or if you two happen to be walking in a similar direction (like to a classroom or the lunch room), strike up a conversation. The goal is not to be too serious, but to simply appear like a fun dude who can make her laugh. That's it - and I don't mean purposefully telling funny jokes like a comedian, but just saying stuff that's lighthearted enough to make her chuckle - if she likes you, you won't have to say too much to make her laugh.
(b) ask for her phone number
It's the easiest, low-pressured way to find out how interested a girl is. Because, believe it or not, a girl does not give her number out to every guy that asks for it - it's usually reserved for the ones she's interested in. So, you're talking, laughing, and just as you're about to break away from her (and yes, you want to wait until you're about to STOP talking to her), just say this: "Well, it was nice talking to you. Hey, let me get your phone number!" Don't ask, don't beg, TELL her to give you the number. If you keep it within the natural flow of conversation, you won't appear nervouse and she won't even think twice about giving it to you.
Very important: once you get the number, DO NOT TEXT HER OR CALL HER RIGHT AWAY. Sit on the number for a few days and let her wonder WHEN you're going to call her. The hotter the girl is, the better this works at making her curious about you and building up her interest.
(c) ask her out
After waiting a few days (minimum should be 4 in my opinion - after all, you're still going to run into her at school, though you should avoid her as much as possible), call her up - read: CALL, do not text - and ask her out. Don't stay on the phone for long - a simple "Hey so and so, this is jgfisherrr" followed by 1 min of small talk, and then: "so, I was going to go see this movie and was hoping i could take you with me." Or some other activity - it doesn't really matter per se what it is, so long as you put it out there.
Once you've asked for the date, SHUT UP. Don't keep talking, or trying to give her reasons why she should say yes. A confident guy doesn't do that - a confident guy asks for the date expecting to get a "yes." So, you ask, you shut up, and see what she says.
If she says something akin to a "yes" - "oh, that sounds great" or "sure, what time?" - it means she's interested in you. If she says anything else that doesn't sound like a positive answer - "Oh wait, is this supposed to be a date?", "oh, I can't, I'm really sorry" (with no explanation or counter-offer for a different day and time) - it's a woman's way of saying "no" without being direct or hurting your feelings.
In either case, you won't know if she likes you until yo do these three things. So, get them done so you can stop WONDERING what her interest is and actually KNOW it. Hope this helps! (Oh, and check out the link below to hear my dating advice podcast!)
