The mind is the biggest attractor. I mean things like personality, intelligence, passion for an interest or hobby, etc. Also important is stability and security.
Well it can't be humour cause we all know your up for a laugh so forget let's see the faces..let's see the butt's.You can even disguise with shades no problem anonymity gauranteed.Fully clothed obviously.
Describing compatibility is hard for me since my interactions with single women have been so limited over the years. Beyond having enough in common, I don't know. You have to have lived to know that kind of person you can connect with.