1.  Only consider those with more than one review or for whom useful information is provided here.  Reject those with different names and telephone numbers, particularly where the older ones have no review history or bad reviews.  Chances are they are outrunning bad reviews.  Reject those with old or heavily photoshopped pix.

2. Avoid those providing incremental services, e.g. a regular price and a higher price for GFE, or that do not advertise a specific length of time.  The former are stingy, the latter are just- get off, get out and be quick about it.

3. When calling, ask how she is doing and chat briefly to test her degree of engagement.  Upon meeting face to face, verbalize your desires, maintain eye contact and watch for vacillation or confirmation that she agrees without reservation before reaching for your wallet.

4.  For the first time, request a half hour session if less expensive.  If all is going well offer more to continue the fun for a full hour.  If you end up getting more than you thought, give a gratuity if appropriate considering the base price.

These could save you mucho dinero, but then again, if you have alot of money & time it may not be worth the effort involved.  Caveat: Maybe over 50% of providers will be excluded.

Finally, I read somewhere that Actual size = 50% of adveritsed size +2"  LOL