Spend a lot of time thinking through exactly what you're
looking for in a partner, including what your "deal breakers" are: being
more specific means fewer responses, but much better matches.
One exception to the above concerns the sensitive subject of body
weight and size: if you indicate in your profile that you'd prefer someone
who is "slim" or "height-weight proportional" (whatever that means), and
particularly if you're a male seeking a female, then many people whom you
might actually be attracted to will self-select out, since the terms are
vague and nobody wants to be rejected over something like that. Frankly,
we'd advise leaving preferred physical criteria for potential partners out
of your ad, completely.
Have a good picture to include with your profile. According to some
surveys, including a picture will increase by a factor of seven or eight
the number of responses you get.
Describe your values, hobbies, and (especially) goals in your profile,
and don't be afraid to mention the "why" behind your life's greatest
interests.
Proceed only as quickly as you're comfortable proceeding, and don't
give someone your last name, everyday e-mail address, personal web site
address, home address or phone number, employer information, or any other
personally identifying information right off the bat.
When going on a first date it's always good to let a friend know where
you'll be, either when you expect to be back or when you expect to call,
and whom you'll be going out with.
The single best piece of dating advice, which gets repeated countless
times but is unfortunately rarely heeded, is to get to a point where you
LIKE your life and its direction before trying to include someone else in
it: two of the biggest things people find attractive in potential partners
are self-confidence and self-assuredness, both of which flow from this.