Ask yourself if you really want to go after this girl. Don’t think too much though. If you like her, give her a try. This does not mean you go and ask your friends if she is “acceptable” to date or hang out with. Word spreads fast. If she finds out you are considering her to be acceptable or not before you even become acquainted, she might find you a bit weird or she might be interested.
Stop any bad habit that could cause her to not like you. For example, if your bad habit is to only shower three times a week, that is a huge turn off. She will find out who you really are eventually, so don’t try to change anything major.
Remember, first impressions are very important – so don’t start a relationship (even if it’s just friends) with lies and/or anything that could make her run away.
Try to establish a basic friendship. This can be done simply by talking to her. Once you are friends, then you can decide if you want to ask her out or not.
Have personal hygiene. Don’t change yourself completely, but take showers frequently and ditch the ripped, stained shirt. Even small things like this can make a big difference.
Talk to her! Whenever you see her, try to start a conversation or just say hi to let her know you notice her. Don’t get on her nerves and be clingy, but don’t worry about saying something stupid. She will probably laugh and think it’s cute.
Put a little effort into how you look. Don’t wear a tie to school or anything like that, but be sure to know your best assets and how to flaunt them! Shine at what you do best and use it to your advantage. For example, wear a shirt that brings out the green in your eyes or a tighter shirt to show off broad shoulders. If drawing is your talent, draw her a picture, this is a really good way of letting her notice you. If sports is your thing, be a star athlete. However, telling her about every single accomplishment you do makes her think you are too cocky and full of yourself, so let her find out the other stuff on her own.
After she likes being around you, pick up the game a little. Hang out/be nice to her friends (even if they get on your last nerves.) Word will travel back to her that you’re nice and sweet to everyone else, and she’ll realize you’re a “hot commodity”. Don’t hang out with her friends too much though, or she’ll think you like them instead.
Make small “romantic” moves. Next dance, ask her. Wish her a happy Birthday and remember her birthday. Hold the door open for her or offer to hold something for her if she looks like she has a lot of stuff to carry. Walk her to her next class. These might seem corny and stupid, but doing it makes you appear as a gentleman. This is a good thing, believe me. After all, most girls complain about chivalry being dead nowadays. One thing that annoys girls the most is when guys make fun of other guys for being a “tool”, “douche”, etc. if he’s nice to his girlfriend. Being nice doesn’t make you a loser!
Find out her interests. Girls love when people know what she likes. It makes her feel important or special. This also gives a small impression that you like her. The only thing to remember is not to stalk or be stalker-ish, a complete turn-off.
Go out of your way to speak to her. Girls love it when they see a guy comes away from their mates just to speak to them. It makes them feel special and wanted. It also drops hints that you like her.
Don’t make rude jokes. Yes you can tease her a bit, but don’t make jokes that will insult her, eg. ‘I hate your top’ even if it is a little bit of sarcasm. And don’t ever make sexual comments (apart from ‘You’re really pretty’ and stuff like that) since it turns them away!http://www.wikihow.com/Get-a-Girl-to-Notice-You