Everything that UTburd said. And most of it is true for women dommes, not just doms.

I think one thing that has really helped me feel more comfortable with myself, as a new domme, is education. I have to know how far I can go when we are playing, I am not comfortable figuring it out as we go along. (for instance- how long can I cut off the circulation to xyz body part? How deep of a indent can make into his skin before I might draw blood? What does it feel like when I pinch his cock here vs there?). obviously some of this learning is "hands on", but if I felt like I was just supposed to show up in a leather outfit and a bunch of rope and a whip, and act out a porn movie, I would freak the *&^ out.

I also agree with previous suggestions that you present yourself to him (whoever him is, whenver the time comes), and simply BE the submissive.