It's always conditional, and I get a lot of negative reinforcement for what vocal people usually profess as being preferable.
More often than not, I contact someone because of their tone and general themes of their stories like the types of characters they play and the archetypal relationships in their plot ideas. Sometimes I do a short email saying I think we may be compatible according to what they say they're looking for and what I'm looking for. I then reference at least a plot or pairing idea, or even something like "your darker coercive ideas". I also gently suggest they read my RT. I'm determining our compatibility to collaborate, not begging for their attention. I hope they bother to check me out too, instead of blindly dashing ahead or expecting me to retype my RT in conversation. I've had the most luck with this approach, even if most threads like this suggest typing more or being specific.
What I frequently get ignored for are my longer more detailed contacts. In those, I write a lot about how what they're looking for sounds like what I want. What I can offer, and I sometimes even type 3 or 4 paragraphs about their plot ideas or some of mine (if they asked in their RT). These contacts get ignored more often than not. So, while I theoretically would like that sent to me, and I try to live the Golden Rule in most areas of my life, I've been taught not to do this for the most part. I spend more time on this than I appreciate wasting, so for a number of reasons, I don't do this much anymore.
The only problem I get with the shorter contacts is when someone replies with a short, stark message asking me specifics about what character I have in mind for their plot. I'm not about to spend the time doing a full character creation before I know if someone is going to ignore my contact or not. So, those don't usually work out after I reply that I'm trying to determine compatibility. But overall, I waste fewer keystrokes than my long detailed first contacts. And, for a little reciprocity, when someone replies with one line like "What are you into?", I roll my eyes because I literally wrote what I'm into and conveniently linked to it. But it tells me that's probably not the right partner for me.
But, I currently have too many partners to keep up with, so my short contacts seem to be the way to go.