Don't forget to reveal a little bit of yourself - your sense of humor, your love of chess (or whatever). Long and detailed, when the details consist of a laundry list of requirements, is as bad as no details at all. So if you're looking for a certain age range, explain why. Perhaps it's because that's your age, perhaps you like more maturity, perhaps you prefer young and naive...

Be open, honest and sincere. That will hopefully bring you responses from others that are open, honest and sincere.

I wish you the very best of luck!