Well, so basically I have this problem talking to girls in my year. Its not that i freeze up or anything, i just dont know what to talk to them about, and often when im around it just leads to an awkward silence. The thing thats weird is that even though these girls are atractive i dont think of them that way (usually it just girls i "like" who i cant talk to, and where friends and all. Yet i still cannot hold a conversation with them for long periods of time, unless one of my friends are arround. I could really use some help because allot of my free periods its just me and them mostly and, it sometimes feals a bit awkward. Help me, please!

Ask them lots of questions about themselves. Girls always appreciate someone who can listen and someone who pays attention to what they say enough to ask them questions about it.

Well if you feel an awkward silence coming on and the conversation is pretty much dead maybe just throw in a "so tell me something"

if the conversation is still salvagable, based off the girls reply really try to ask questions based off that or if its starting to dull down ask something closely related to it, it shows your listening to what she has to say and often she'll continue on the subject

lol I had a friend in high school who whenever a silence came said 'sooooooo' it made everyone laugh. Didn't really start/keep the conversation going, but it was better than silence.

Okay. Here:

A lot of guys, and girls alike have this problem. It goes back to the whole "Oh, I don't know what they like and don't like" bullshit. Just start talking about something, and see how she responds.

OR

You can actually ask her what she likes, or ask her if she likes this, or if she likes that. That would be the best way to find out what to talk about. Then, you would also have some common ground with her as well. =)

As Raeillieagh said, it's just kind of a matter of getting started. And finding things she likes to talk to her about is good, especially if it's something you both like, or dislike. You might also try observing (unobtrusively) her and see if you can pick up on something she likes to talk about, read, etc. Just don't stare all day or she'll get creeped out. And do try to be yourself. In my opinion, it's always better for someone to get to know you/like you for yourself, not some image you project.

Although I will agree, often times it's hard to screw up the courage to talk to someone you like. I try to think of it as, 'this is just another person so I'll talk to them the same as anyone else.' Doesn't always work, but it's a thought.

I talk about random objects, though that may work only for me...
ex: "gosh, that plant looks like it hasn't been watered in decades! I wonder what kind of plant it is. Do you like plants? I like green beans."
"I wish I had a hat like that. Do you think I'd look better in a green hat or a blue hat?"
"I used to have a bookbag that color. Do you prefer one strapped back packs or two?"

um... I think you get the idea of the random object thing.
I'm with Raeillieagh as well, try asking what she likes, it may suprise you.

thanks, for the help. Ive tride what was suggested, it helped, thanks.