i'm not exactly sure on the questions you are asking but I think I can help you understand the first question "how he used them".
Originally Posted by Al.
He used his fear and deception to take control (or sway to do his work) of the evil men, easterlings, and orcs. With the orcs I would say it is mostly out of fear of him that they listen to him (as well as a natural order of things and natural evil maybe).
The Easterling as well as evil men had their own motivations so that Sauron could easily sway them. I'm not sure if that is written by tolkien anywhere but I would assume they fought for him for their own motives as a mix of other things (a little bit of fear, bribery, deception, promises, etc...).
The fear he used against other enemies (Men, Elves, Dwarves) would be the fear of his power (orcs, easterlings, men, nazgul, etc..). Most of the time Tolkien talks about men running frightfully or something in the books it is because of the Nazgul and their natural aura of fear. I would assume Sauron would be able to let off an aura like that if he so chose to (assuming he has the power left to choose that).
I hope that helps somewhat. Just take what I said with a grain of salt however because a lot of it is assumptions.
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