just talking to them is a good start. chat with strangers about anything, it doesn't have to be about any specific topic. Getting a job in sales has taught me a lot about approaching strangers. if they ignore you or are condescending, you lose nothing but the time you took to say hi.
it's the same thing with dating. If you just want to date around and test the water, and the girl you take out turns out to be wrong for you, all you've lost is the time you spent with her. If it turns out otherwise, you stand to have a great time together.
I'm going to give you a bit of homework, plan9 style (you might want to consider his
"getting girls 101" thread, as he is much more experienced at simply "scoring"). My talent lies not with women, but with getting along with just about everyone. I've already got a girlfriend and the only reason I talk to people is to hone my own basic social skills. Just because I'm not "on the prowl" doesn't mean I shouldn't speak to anyone.
here's your assignment: talk to at least one stranger every day. doesn't matter how long, doesn't matter what about, just talk to them. say hi, ask their name, whether they've found jesus yet, ANYTHING. you'll quickly realize that you lose nothing but your own inhibitions when you strike up a conversation with a total stranger. The easiest way I've found to talk to people is to make a comment about a current situation you share with them. Something about adding classes, high tuition fees, the long line to talk to an academic advisor, how bad the music is at the party. This will help you to think on your feet, you'll find it's easier than you think.