How do I approach girls I don't know?

Me being the dork I am, when I think someone is good looking I will just come out and say it... "I just wanted to let you know you are super sexy...what are you doing tonight" I have gotten guys that way...
but I guess its different for the opposite sex I would think a guy was making fun of me if he did that to me...but it could work..
You could even just go up and say hi, if you get shut down try it again on someone else.

Be who you are and I agree with crazygirl compliment her even if its something as small as her smile or her laugh or anything girls love that... ask her what her name is and show confidence but leave out those corny pick up lines some guys like to throw them in thinking they are good but they really are not.... for me its about personality I like a guy who is not afraid to say hey to me and ask about me you know? one who even though shy is confident with who he is and is not cocky or over into him self your shy so that should not be an issue unless you get nervous so be careful... if you have any female friends that your really cool with have them come along and maybe help you out a little they could even make friends with a few girls and you can start by talking to them like that but don't make that a habbit maybe just to get started it could be fun you just have to get used to it I'm sure you will do great!

Be confident and sincerely compliment them. Girls like it even when they act like they don't. If you are old enough to buy alcohol buy them a drink.

You have to be yourself. I know you've heard this line over and over, but it's true. When you're at the mall, don't go up to a girl and talk about how you just got voted MVP in a soccer game when you don't even play soccer. Just go up to a girl and ask if she knows where a certain store is. When she is showing you how to get there, start a conversation. When you get to the store, maybe ask her whether or not you look good in a certain garment, or if she likes how a certain cologne smells. This is just one idea. If you open your imagination, you will be surprised at what great ideas could come out.

I COMPLETELY DISAGREE with Crazygirl, she's just after validation and free drinks. But if you want to try it, go ahead. Go to a bar, compliment women, buy them drinks and maybe a couple of roses from those night club flower guys, and see how many girlfriends you get. Seriously try it, go waste your time and money.