[edit] Steps

Don't force yourself to get over someone. You just have to let it happen. The more you try, the harder it is. Trust me!
When it happens, take a week or two and just explore. Does anyone just pop out at you?
If not, just keep looking. There's nothing worse than hurrying!
Day by day, you'll notice someone. I guarantee it. A guy you barely know or a best friend you've never seen as a guy. Seriously, it could be a guy you NEVER expected it being!
Next, you have to show him you like him. Is there a dance coming up? Don't ask him to the dance, but when you're at the dance, ask him to slow dance a lot! He'll start to get the point.
Have one of your friends call him and ask him what he thinks of you, then, have your friend tell him to consider liking you. Have your friend compliment you as if saying to the guy, "You should like her! She's pretty, smart, really nice!" (Unless you know that friend has a history of flirting with guys you like, then don't. Otherwise, she might end up getting the boy)
Then, the final step, have your friend tell the guy to ask you out. Have them say "You should go out with her! You guys would make a really cute couple." And have your friend make him ask you out on the phone.

[edit] Tips

Remember not to seem too desperate.
Don't be all over him, remember. At a dance, don't ask him to the dance, don't scare him. Ask him TO dance! Not TO THE dance! (If you get what I mean!)

DONT care about who everyone else thinks he is. He may not be popular, he may not be the hottest guy in school, but the greatest guys are found by not caring about popularity and looks.