FOR GUYS: These are pretty much the things that get me. I can't speak for other girls... but.. I'm speaking for other girls. We all like the same s**t. xD
-first off, SMILE! I know you've probably heard that, but when a guy smiles at you a lot, you definitely notice, and smiling is sexy. seriously.
-Talk to her. Obviously, things will get nowhere if you don't talk to the chick. Find a common interest, and then TALK about it. And common interests don't have to be huge, if you hear her talk about bananas, you jump right in there and talk about bananas. Talk about how you just love to write the word banana. It's an interesting word, isn't it? Banana.
-TELL HER TO HAVE A NICE WEEKEND!!! sorry. um yeah, that happened to me once and it pretty much made me smile ridiculously for the rest of the day... Figure out how to make it sound original, if you can, make it MORE than just a friendly "have a nice weekend" make it like... you both say bye, and as you're leaving, turn around again and THEN say it... as if it just occurred to you. It's more memorable that way... I think... *blushes*
- Complement her. When she's wearing something nice, or better, new, say you like it. If she's got pretty eyes, hair, smile, say it! But you have to remember to be tactful about it, you can't just run up to a girl and say "I LIKE YOUR CLOTHES!!1!!11" Complements are supposed to be like little unnoticeable comments. If she likes you, she will notice you said it. Trust me, girls over think EVERYTHING. If they like you, they will probably remember everything you have ever said to them. EVER.
-Lean over her (if you're taller) and get a bit close. Give a girl too much space over time and she'll think you're not into her.
-Find a chance to touch her. Just in small ways (if you're not confident that she likes you). If she feels for you, she will be happy, and if she doesn't, she probably won't even notice it happened..
-Hold the door open for her. You may think that's dumb, but girls find that really considerate, and its showing that you actually give a s**t.
-YOU ask HER out. Don't you dare complain that it shouldn't be the guys responsibility. You pansy. Get some balls! Anyways, if anything, girls are just really flattered when they're asked out. Also, don't ask it out of the blue, make sure she knows you exist first, that brings up your chances by like 600%. Think of it this way, when she says "EWWW NOOOH YOU'RE GROSS!!" at least you know that she definitely doesn't like you. Stop wasting your efforts on her, and move on to that other girl that you always thought was kinda cute...
-FINALLY (do you know what I'm gonna say) be yourself. SO CORNEY! I know. But being yourself is confidence. And confidence is way sexier than any other not-yourself person you could possibly be.