Chi61... excellent advice. In my heyday I may have had six, eight sessions a year with mistresses I respected and considered real pros over a few decades. I'd add a few more points and not in order.

1. To abstain days, weeks before is great for you. For the Mistress... it might be entertaining for her, but you never know.
2. Do as much research, networking, etc. as possible before scheduling sessions. In all I have done, over the decades, it is best to make an appointment with the head on your shoulders versus the head between you legs.
3. It isn't all about you. I started out in the pre-online days. I always assumed if I went to a Mistress' home/workplace or dungeon that she thought I could be part of law enforcement or an axe murderer. It is easier now with all the deposits and online tools to find out who you are (and who she is) but be respectful. Act like YOU have been hired by HER.
There's more, but it's all about respect, dare I say fellowship.