Athena brought up a very good point. There isn't anything that I've done to a guy that I haven't had done to myself, first. Except for cock and ball torture for the obvious reasons.
This includes spanking, which I've done a lot of. I'm not into spanking done on me but the point is, you need to know how things feel before administering them. That REALLY helps.
There are a lot of escorts, and I'm not suggesting that you're like this by the way, that think that they can make a few extra bucks doing Domme work. And it just isn't a good idea at all. Again, this isn't the case with you, I know.
So ... the poster above was right. You need to start somewhere. Since I agree with Mia and you're probably going to go for it, start light and ask for some guidance.
Oh ... quick hint. Don't ruin the moment by asking a submissive, "I'm not hurting you, am I?" Cheap advice but it has served me well.
Safe words are important, too.
And try to scroll to the many pages of topics here. Doing that is going to give you a lot of ideas.
There are also some books, too. Jay Wiseman always writes good stuff.
Here is a decent starter book:
http://jaywiseman.com/MER_SM%20101.php You can probably find this on amazon as well.
There is also a comprehensive reading list somewhere in this forum if you wish to start studying further.
Good luck,
Elisabeth