1) There is no 'normal' in this game, just preferences. Evidenced by the variety of providers in all sizes, shapes, colors, and kinks. Personally, I like variety but if I find a provider that clicks with me, I will stick with her for an extended amount of time, or time she is available. Usually two to three months if she is 'local'.
2) If you find it awkward, create an alias and write the review under the alias. If you are giving her glowing 10/10 scores, not awkward. If you are giving her 6/6 reviews for awesome service, yeah, awkward for everybody involved, including people reading your review. Don't be 'that' guy.
3) Remember she is in it for the money. While she may hate you less than other guys, its a business. She isn't going to hang out with you afterwards, extend your time, etc. If this does happen, count your blessings, she doesn't have an appointment booked right after you, and you're probably not giving off creeper/stalker/serial killer vibes.
3a) Don't fall in love with a hooker. If you do, empty out your bank account and put all the bills in a pile and set fire to it. Does it happen? Yes, but very rarely.
4) Be clean, squeaky clean. Most importantly, teeth and mouth (brushing is not enough, and flossing just as you head out the door, probably not good enough - halitosis is a session killer). Followed by clean and filed fingernails and toenails. Women get infections easily, and your dirty little hands on or in her pussy is a good gateway to getting an infection or scratching an inner wall. Keeping your junk clean, in the crevices, and ass. If you take a dump, take a shower, even a tiny little bit of residue is noticeable. She is a pro and won't mention it, but it will make for a less than optimal session. If your bush is well, bush, trim it. Tug on pubic hairs and remove loose hairs, or she'll spend time picking pubes out of her mouth - not sexy for anybody.