Things You Will NeedOk, first things first you don't need anything but your self. Though expensive clothes and a new sports car never hurt, the only thing you really need is a little confidence. So just keep this thought in the back of you mind to begin with. I'm a great guy. Also keep in mind that the worst that can happen is that she says no. In this case you haven't lost anything for trying. Ok now that we are confident lets try this a little defiantly.
Step 1Alright step one is pretty obvious walk over and introduce yourself. Don't try any corny lines unless your trying to make her laugh. She's heard them all and isn't going to be impressed.
Step 2Ok step two is going to be a little tricky. This will call for you to be able to think on your feet. Make a comment that is relevant to the situation around you. Then ask something casually such as so are you from around here. Remember in all this to stay calm and confident, after all she is lucky to be talking to such a great guy as you.
Step 3Step three is one your going to want to remember. Keep it short. Rambling is never a good trait.
Talk for a few minutes and then make it clear that you have to run, but that it's been nice talking. Ask for a number to continue the conversation at a later date. Or conversely with social networking such a big thing these days ask for a user name to add her and talk online. If she says yes then the hard part is over and feel free to progress at your own pace. If she says no be the gentleman and tell her you had to give it a try. Then walk away.
In closing just keep in mind that you won't always be successful. Just don't let this get you down, though she might not want to talk the next girl might. All woman are different and you will develop your own style as you get better at talking. Just be confident and in the end you'll get the girl.