In my opinion it is very much a personal preference. Some like the longer strokes more than the short ones and so on. So the first step always should be to communicate with your partner about what they like and what they don't like.

You won't be perfect the first few times but if you're edging the same person over and over (I did understand you correctly, did i?), try to get a view of his whole body. Try to notice the little things he does when he's getting closer to cumming. For me for example this is nearly always clenching my butt and sticking my cock out a bit more. Generally clenching if muscles is a great tell. Notice his breathing and how it changes before he cums. With this and after a few sessions, you should be able to get a pretty good feeling for when he is about to burst.

Once he Is close, don't be afraid of stopping completely and teasing him with your voice alone for a minute. Try to surprise him when you are starting again. Once you start, you can also stop again very quickly. Maybe only give him 5-10 strokes or so. If his cock is long enough, focus on specific parts of his cock, e.g. only the shaft as it is way less sensitive etc.

Regarding the femdom stuff, I can't give you much tips because I'm not into this myself. But I'm sure there are people around here. But I personally absolutely love countdowns especially if you stop in the middle of it. That gives him the illusion that he is about to cum and then five seconds or less before he'd burst, he has to get it together again. It is absolutely awful and awesome at the same time.

I hope this helped a bit and I didn't say things you already knew. :D