I generally had a fantastic time with the girls I originally chose, but a few times recently have been some lame experiences, and I'm not sure what the dividing line, and I'm not sure if I was just getting lucky. What is the average? In the past I chose girls that ended being very fun that I felt I could connect to. Now that I think about it, my bad experiences were with Latinas, and I'm most attracted to Latinas! I did have a great experience with a super-fun Colombian (who I thought actually talked to much) even though she wouldn't get naked, and I ache for that compared to my last few experiences.

Also, a little confused by the great experience you had with the Colombian who wouldn't get naked.
What did you do with her, play video games? ;o)

...here on TER. Check the profile and read the entire review. Then see the lady of your choice.
It does sound like you are picking by pictures and taking your chances. When you do it that way you get what You got. Some are good and some are not.

On top of checking reviews, which is the gold standard, I find that I get a good handle on a gal's personality from the way she posts, and if I like that, then that bodes well for the chemistry that is so important.

I zero in on providers mainly based on reviews and profiles (including ads/web sites and photos), but sometimes I see posts from a provider on the boards and get a strong feeling that I'd really enjoy meeting her and we'd click. And that feeling has never been wrong. Yet.

+ 1 on this. We all have our 'type' as far as looks go, I personally like women that are 5'6-5'10, 130 pounds with D cups, or DD. I can often find that exact match if I use the search functions. Beyond that, I read reviews and book dates with providers who are in other guys minds at least an 8 on looks and mostly 8- 9 on performance. Thats a general rule and I have good dates. Lately, I have had enough provider okays and have been dipping in the pool more frequently, so I have been looking specifically now for 9-10 looks and 9-10 on performance. I pay more for that, but wow. These women are really, really hot and do just about anything.

I look all over, and have to be physically attracted to her, first of all.  Next, I check the price to see if she is in my budget range.  Needless to say, I hate it when she posts no rates and wants me to contact her for rates.  Those, I usually pass on.  At this point, if looks and $ are in line, I start doing the research.  Reviews first, check pics, phone.  If all these are ok, then I make contact.  

Read the reviews. Build yourself a list of trustworthy mongers.