mrfisher gave you excellent advice, as he usually does. As being new to this enterprise, I'd suggest you stick to well-reviewed providers. yes, outcalls can be expensive if you have to get the room, so I agree that you should start looking for incall providers. Preferred411 allows their providers to indicate if they are newbie friendly, which means lighter screening, I'd suggest joining there and do some research.
VIP here is very necessary for your research, w/o it you can not read the juicy details of reviews or see the ratings and fees for the providers.
Most providers, if they are good quality ones, will indicate somewhere, usually on their website, how to handle the donation, and most want you to put it somewhere where they can see it when you arrive.
Backing up to your first question, tipping has been discussed here many times, do a search of this forum for it and you will find lots of ideas. Most providers will not require a tip, but they always appreciate it. If you feel the service was top-notch, by all means, feel free to let her know with a tip. Many have said the best tip is a return visit to her in the future.
Def read the self help center ASAP!
Swim