1. Be clean. Brush your teeth, floss, shower, wash your hair, and apply acne medicine (if you have a problem with your skin) daily! Notice how girls have fewer zits than you do? That's because we know the wonders of hygeine. Don't wear your pants off your butt, it's not that attractive to the majority of girls. This is essential if you are even going to approach an attractive girl. Wear clean, attractive clothes (if in doubt, get an older sister or close female friend to help you in this department).
2. Have a good attitude. No girl likes to watch a guy put on a show, so be yourself. Don't try to impress everyone - girls like humble guys. At the same time, a sense of humour is always a plus.
3. Show respect. If you respect everyone and give them their space, they'll all respect you. With girls, it works even better. If they see you respecting everyone, and not getting pushed around while you're at it, they will be reassured that you will treat them right. Be kind to all.
4. Have good conversations. Don't talk about how you beat the big-bad-boss on level 23 gazillion of a video game...unless you know them well enough that you know they play that game. Try to aim for you both to be speaking 50% of the time, but make sure that you are saying something worthwhile; it's not attractive when only one person talks endlessly.
o The #1 mistake when talking to a girl is focusing on yourself. Girls are way more comfortable when they talk about common interests. Ask about their interests, hobbies, favorite books, music, etc. but not in that stalker kind of way. If she asks you a question, answer it in a few, short sentences and then redirect the question back at her. This engages her in the conversation. When in doubt, compliment her. Be careful when complimenting her on her clothes, however. "That color looks good on you" is okay, but "I love that dress!" will make her gaydar go off.
5. Try flirting! If you both make eye contact, do not be the one to look away, but do not stare for too long. When you both make eye contact, just give a slight smile. She may look away and she might blush a little. Be careful though; you don't want stare her down. A good move is to look away, and if she likes you she will shoot you glances. Watch for that.
6. Respect her friends and their ideas and opinions. Always speak highly of her and never talk trash about her. It will damage her reputation and yours and she'll possibly dump you. Of course, her friends are going to tell her that you trash talked her. Hopefully then it will work both ways - she will be tolerant of your friends. Be careful not to compliment her friends too much, however. Example: You may say "Your friends seem cool. We should hang out with them and my friends some time, I think they'd get along". You may not say "Sally is so pretty. She has the nicest eyes".
7. Be polite to her parents. Be kind to everyone, especially them. Don't be too over-the-top charming with the parents, however, or they'll think that you have something to hide.
8. Don't criticize her.
9. Be romantic, but not over the top. If you've been dating for a while you may attempt a grand romantic gesture (note: "A while"=a month MINIMUM) otherwise, you'll look like a stalker.
10. Start talking to her casually. If you don't know her, make friendly conversation. Ask for the time, and/or compliment her watch.
11. Do not play "hard to get". Sure, you'll get their attention for a day or two then after a while, the girl will end up frustrated or think that you hate her for whatever reason. Or if she likes a guy who's like that, her friends might not like you because you're acting like a jerk (this happens way too much).
12. Be careful with what you say. Remember, Hotty McHotterson is not your pal Lenny. Do not discuss bodily functions in her presence, or make jokes of a sexual nature unless she starts doing so.
13. Hum a few bars of a song she likes around her. She might think of you whenever she hears that song. And she'll probably be impressed by your good taste in music. Some girls have actually dumped guys or stopped liking guys when they insulted the music they like. So, it's OK not to like her music, but don't be insulting her favorite singer/band! Try to agree with her as much as possible but not so over the top that she knows your not being yourself. Make sure the song is not overtly feminine however. For instance, a Killers song is okay, an Ashley Tisdale song, not so much.
14. Start an inside joke with her! She will feel included and become closer to you. It also gives you an easy-to-come-up-with conversation starter. Try not to overuse it and kill the joke.
15. End later meetings with a hug, or plans to meet some other time, if you can. Do not tell her that you "like her". Ask her out. If she rejects you, all is well. Example: You: "Betty, want to go to dinner on Saturday night?" Betty: "Sorry, I just think of you as a friend" You:"No offense but I wasn't asking you out, a bunch of us were talking about going"