Q: I am new and have a few questions - first, what is the best way to protect myself when providing to females?  
A: Bring a dental dam with you.  They can be found online or you can use saran wrap or open a rubber.

Q: second, what is the best way to know if I am being set up by a cop?
A: Don't take chances, see well reviewed providers with known reputations to lower your risk.  LE uses different techniques and will discuss money and sex for the most part.  If you end up in their hands, they'll probably bust you no matter what you say/do.  The key is to not take chances in the first place.

Q: finally, is it OK to say full service on the phone?
A: NOT a good idea.  Many will hang up on you if you start discussing sex or say full service to them.  You can ask if the price per hour is all inclusive, but that shouldn't be a question if you read the reviews.  Pony up and buy a membership, it's worth it.  

Escorting isn't illegal so time charged per hour is exactly what you CAN discuss in emails and phone.  Anything else can get you and her into trouble.  Oh and you'll get more mileage if you ask if she needs a new set of wheels instead :P

Hope this helps.