I met my current girlfriend of 11 months on CL, and have met plenty of other great people there as well. There is a trick to it, I'll try to lay it out briefly since I've posted about this here before.
Post an ad yourself rather than replying to ads, many are fake and will just add your email to their spam database. Make them come to you so you don't put your email out there.
Post a pic! Very important, no one will take a chance on a pic-less ad.
Use a codeword! I can't emphasize this one enough! This is how you filter out the bots, and will change your entire CL experience. It's really simple, in your ad just conclude with "serious replies put X in the subject line" where "X" is your codeword. Make sure it's not something from your post title or really ubiquitous, the best are things like "put your favorite movie in the subject line" that require some thinking and can't be automated. Any replies without the codeword in the subject line go straight to the spam box.
Don't post thinking you're going to get laid the same night, that seldom works (I won't say never because it has...), but it usually comes off as desperate and/or sleazy. If you want a date for Friday night post on Wednesday afternoon, this gives you time to chat with any promising replies and further check them out. You also can run any email address or name you get past a few social networking sites (Facebook, Myspace, etc), this can also help weed out any fakes.
On a related note, use a separate email from the one that you use to register for forums and social networking sites, it's way too easy for someone to run down all your personal information otherwise.
Everything else is pretty general to dating sites, don't put out too much information (they don't need to know your AS status until/unless things get serious), be honest about yourself and what you're looking for, and try not to be creepy.
Good luck!
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Your boos mean nothing, I've seen what makes you cheer.
- Rick Sanchez