Punting is a system built on rules, some of those rules may be bent, others may be broken.
For me the choice of actual SP comes down to physical attraction, services, and reviews.
Obviously the dick casts the first vote, I see the profile pics or read a review here and a girl instantly appeals and gets me stirring, or not. Hence there's nothing worse than arriving to a b&s or even just where the pics have obviously been doctored or are out of date. I rarely see a girl without seeing face pics and often when I do it's a disappointment. But then take the likes of MissKDD - no face pics, hidden feedback, but blinding reviews here - she is one of my all time favourites and one of the first girls I think of when ticking stuff off my sexual bucket list so it was the best decision to break that rule, based on the reviews of trusted punters here.
If the dick is stirring then I filter by services to see if she does all my essentials - for me OWO, DT, RO/69/rimming (on her), CIM are probably the must haves. There's rarely a case where I'll see someone without all those on the list - but it does happen, and I've had some great punts as a result. I'm even looking to see a girl who doesn't do OWO let alone CIM which will be a novelty, but then that's the point, she is a novelty, a contortionist and a big tick off my bucket list. Again, rules made to be - ahem - flexible.
After I've evaluated the services then I check reviews here. A neg from a trusted punter here is usually enough to get someone straight on my blacklist. But, then again, sometimes an sp occasionally gets mixed or negative reviews here like Smiley Miley, yet still keeps bubbling to the top of my hot list because she does really make my cock stir. Generally though the big head keeps the little head from making those decisions as there are still many others to see who may not fit my physical ideal but have a broader service list and better reviews. Most times when I've let the little head decide I've lived to regret it.
As I mentioned though my priority is usually to tick items off my sexual bucket list and that often drives my choice of service provider. What I have found is that for many items on my bucket list I need an sp I can trust and rely on and who is willing to try things that others wouldn't. So I have a handful of great regulars with a broad service list who I have a good rapport with and am gradually ticking stuff off with them rather than taking on more girls. With that in mind I have the delectable MissKDD lined up again this weekend - now I have a few days to go through my bucket list and figure out what I'm going to do with her.
Ahem, I digress, so maybe if I have one hard and fast rule it's this - don't let the little head make the final decision. No matter how much he's stirring, set some basic guidelines and stick to your guns as it will result in better punts. I'm still batting at something like a 95% + for positive punts and when I have gone wrong it's from letting the little head override my judgment.