I've read many times that when screening a provider, you should Google her phone number and search her photos on Tineye. When I do this I usually see her photo or phone number on a different BP ad in a different city or state. Sometimes there is a quick review on another review site. What kind of positive info should I be looking for and what info to be wary of?

Tineye or Google images...  multiple image hits over wide areas indicate they pictures are "stolen" internet images.  Especially if they have several years of returns...  they are sure not a "new" local girl.  Sometimes they'll even turn up the source image...  like a bikini picts site or porn.  

0 or 1 local return on picts increase the likelyhood that they are really her.    
 
Searching her phone number may find reviews or ads outside your area or outside the Ad Venue you are using.  

Since this is the Newbie Forum...  it is highly recommended that Newbies (and the risk adverse)  see well reviewed providers...  that is providers with 6-10 reviews including some by experienced reviewers (with 6-10 reviews themselves).  With a well reviewed provider, you can read the full reviews & be as assured as possble that she is as advertized.  Experienced reviewers have a sense of how things should go & can often avoid problems.  
Clearly not every "Newbie" follows this but it helps avoid disappoinment.  I'm not saying "never" see her but keep a eye on her reviews...  circle back after a few & see if you still want to see her.  
I had some I was glad I passed on & some went onto my 'to do' list.

Before contacting any provider, you should Google her phone number. See if the number pops up for ads that have different cities, providers or phone numbers on them. If the result only shows the provider in question, then that is a good indicator that she may be legit.

Use browser addons like Tineye and Google Images to search the provider's photos. (I usually get better results with Google, but ymmv). If the photos are of a porn star, or come from a site like vk.com, or are of a provider who consistently advertises in another area, then move on.

Some other things you can try:

• For phone numbers, check at least 5 pages of search results.  
• Try removing the dashes, parentheses or stars from the phone number.  
• Check the cached copy of the ad. Click through the pictures in the cached ad
• Do a Google search of the provider's email address. A Spokeo.com search is even better, but it will cost a little.
• Google a portion of the text in the ad.
• If you right-click a photo to save it to your hard drive, you can see its title