This should be obvious, but my tip: only see SP's who have good reviews, I learned that the hard way. I see a lot of guys getting scammed and fooled, and it could be avoided.
My first time (when I was a dumb 21 year old), I picked an SP from the Mirror, and I ended up with a bait and switch. Her pics were heavily photoshopped (if they were even the same person), and she looked 10 years older than the ad; the experience was mediocre, she wasn't too clean either, and I ended up masturbating to orgasm on her belly (after a lot of mental effort).
Since then I've always picked SP's with reviews (about 10 so far), and haven't had a bad experience. I've had a few passable ones (one girl wasn't really into me during the gfe and it was awkward; I lost my anal virginity to a TS, and didn't like it), but most have been amazing.
So gentlemen, please, if you see a new SP who looks good, wait for reviews of her to come out before you take the plunge.