I've found that there is no "right" or "wrong" way to have an RT. Sure, certain builds will entice more people, and a good rule of thumb is to describe exactly what it is you're looking for, but none of this is absolutely necessary. Interestingly enough, on my own RT, I got far more interest when all I had were basic pairings, not the in-depth plots I have written out now. I didn't even have an F-list until fairly recently! To this day, I get more attention on pairings rather than my established plots. Not that I mind at all- I've just noticed more people want something open-ended rather than something I've largely already built in my mind that they might not feel that they can wedge themselves into.
Another thing? Sometimes an RT isn't even necessary. A couple of my longest, most enduring, and, dare I say "favorite" RPs are from people who have no RT at all. It's a gamble, I understand, for some people to take up a plot with someone who doesn't have one, but it's something I've never once regretted.