What are your needs and wants, what traits do you want in the other person.
I am excerpting from a manual some of my friends wrote back in 2000 that was intended to help one figure what they want and how to go about finding that other person in the world of BDSM. This is only one part of it and it has many more chapters that I may post some time in the future. Keep in mind this is written with the submissive in mind but applies equally to a dominant or master and just plain vanilla.