Well hello there! I was in your situation where I just found it hard to get in the hobby. The providers on craigslist that I did meet with no references (had to give hotel room and last name) were not quite good experience.
I ultimately found luck with a college girl (in different city) who used my linkedin to meet up for drink in bar first. On two occasions, I have sent an unsuspecting email from my work with something like "hi, do you still have that Gopro for sale?". Of course, both ladies had created a new email account for me to send email so that it was not searchable on google. It worked as they wanted to have my real ID from work email.
I have never used an agency so far because they want to put name and employment info in database. That I will never do. There is one in Boston run by lady called sexyjill, she has v nice cast members at very reasonable rates but I can't get in her club for reason stated above.
Finally, I would say I have been 40% times extremely satisfied with my choices. I started a thread earlier here on topic of 'sending a girl back' if you don't like. I have never done but would be forced to if the success rate remains low.
Generally while looking for a provider of your choice, if there is specific requirement, make sure there is compliment on that feature for her. For instance, beautiful face, perfect body etc. if all the reviews praise her attitude and other stuff but none on provider face or build, then you know the answer. Good luck