The connection thing is obviously big. If two people get along the sex usually takes care of itself.
Having said that; and many of what I'll say after this pertains to physical, but this point is really the key ingredient.
A provider does the job.
A good provider gets along with a certain type of person (or maybe a couple ie she's quite ymmv and not just with hygene/politeness)
A great companion gets along and forms that connection with a great many type of people.
The most important thing about being a great escort is being upfront about what you are (ads/webpage) and being able to read someone, nobody expects you to be a mind reader, but being observant, intuitive, and be able to react to what's in front of you appropriately will go a long way.
Random other stuff
There's a fine line between not rushing and dragging things out (speaking primarily of preliminary stuff like talking, touching, etc). Cant give you specifics as it's mostly read and react type stuff.
Be prepared to make the first move or lead (otherwise state it on your ads/webpage). This isn't just physical, but during conversation as well. Some people are shy, and need to be nudged to get going. As you may have seen from many other reviews "she made me feel at ease, comfortable, etc..." "we talked like old friends"
Some guys dont like to constantly be asked "what now" but some guys are just shy and dont really say that you might not be doing something the best (read body language, if I guys hips are trying to force themselves through the mattress you're probably being too rough during the bj - that's fairly obvious but I've had a lady ask me why and wtf was he doing?). A lady I saw varied her technics a ton with a range of activities and paid attention to my reactions, as time and sessions went on she had her technics fine tuned to what I liked. A good to great escort can do that for a repeat client, regular to good escort doesn't and just basically keeps hitting the same points.
Conversly, dont you be shy. Some guys are really into mutual pleasure, unless someone is obviously into what he wants to do, maybe he'd enjoy you pointing him in a direction that you'd like the activity to go (ie daty, lots of us really like doing it, but not everyone wants it to be done to them the same way - maybe dont let a guy fumble around till he finds out what works for you and just point him there, words work, body direction generally works better and is a little hotter.....it's actually a lot hotter). Hell some guys like to be asked to do things.
Try to be a little creative. Nearly everyone goes through the CG, Mish, Doggie routine. Break it up, toss in some other positions of your own accord, this gets remembered. This also does not just apply to the physical. Things that are different stand out, things that stand out tend to be remembered. For me personally, ladies I remember I like to see again.
Try not to have your compliments sound like "lines". Most women dont like when a guy approachs them with a line in a bar. We as hobbyists dont really want to hear the same things we've heard from the past 5 ladies.
Some guys dont like asking for services. Offer them. This is very specific to me but, I like to give a facial, but I'm never asking to do it, the very rare time that a woman just goes for it it's hot as all heck and I definitly remember. If I have to ask to do something, it does take some of the fun out of it (see the guys that mention the best times are the ones that it doesn't feel like service). Unless of course what you're offereing is an upsell (upselling can be bad for me personally not because I'm paying more - usually it's on an ad and I know beforehand - but because it makes me feel like I have to do that thing even though it may break the flow of the session ie "cim is $50" "sure I can go for that" but what if when the time comes I'd like to just keep up with fs and finish that way or "gee those are great breasts, I'd like to cum on them!" either I break what i'd like to do and cim just because I paid for it or I dont and think "fuck I wasted $50!" either way, it could impact how I remember things). So if you'd really rather not do something, it's probably best not to offer it on an upsell and just make an all inclusive rate. IMO the gfe and pse seperate packages tend to work well for that; but be prepared, to some guys gfe and pse just dont mean services it literally can mean "feel" of the date.
Lots of people treat others (conversationally and physically) as they like to be treated.
The experience should be filled with positive energy. Keep up beat. If you cant, dont work. Minor annoyances can be ok to talk to clients about. Much complaining.....is a mood killer. There's a difference between just having sex with someone, and being erotic, turning them on beyond "omg she's sexy looking". Mood/atmosphere can be just as important as chemistry. The client obviously wants you because he's there in the first place, make him want to be with you even more once he's there (this sounds purely physical, but it isn't), do that right and he'll keep wanting you once he's left.
Last, he's (or she's) paying you to make the time about them. I dont think a woman should give me service for free or at a discount if she really enjoys our time together because she makes that time focused on me. It sounds obvious but sometimes ladies forget it (obviously this is assuming personal limitations and boundaries of the provider aren't being pushed)