What are good things to say in an ad? What are bad things to say (especially, when you don't offer bbfs?)? Thank you for any & all advice!

Especially if you want your ad to be posted. Start by reading the directions.

More specifically, the Provider Ad Posting Guidelines:

http://www.theeroticreview.com/discussion_boards/viewmsg.asp?BoardID=33&Page=1&Messageid=75528

You must have a link to an ad, a website or your TER reviews for starters. The TER banner must be on the linked site and must click through to TER. Only one ad thread in a 7 day period.

The newbie FAQ will answer many questions.

Pictures! A pic would be the best reason for me to read an ad. If I don't like the pic, I won't read the ad.
In your case, just don't say you are GFE in the text.

BTW, you should learn the proper acronyms and terminology. NO providers are advertising BBFS on TER.

But apparently you can use hair to cover them - http://minneapolis.backpage.com/FemaleEscorts/im-the-hot-gurl-next-door-19/5408983  

Or a pair of aces - http://minneapolis.backpage.com/FemaleEscorts/o-o-o-o-your-new-addiction-o-o-o-o-sexy-petite-playmate-o-o-o-o-18/5368127

Or if it's just 1 tit, you can use your hand - http://minneapolis.backpage.com/FemaleEscorts/exotic-hot-tie-new-pics-22/5435938

In fact advertising BBFS will send people away and may even get you kicked off the site.

A photo or two,cost/hr and general location. if you are 100% covered say so, some guys prefer it and some will pass by and not waste your time.

Cost is a really helpful piece of information.  It helps do away with an awkward questions.
It has also been my experience that rate information in the ad leads to a session with less upselling.

I spoke too soon. Those pics have been deleted.

is what I will do if phone, cost/hr and photo are not in the ad.   I don't ask questions and if I am expected to pay her what I think I should I can almost guarantee no matter what is given she will feel short changed.  Simple, if the lady has a value in mind she better post it to get it!

You have to earn the privilege to be on the provider board.
Start by reading the newbie board.  That's what I did.