I think slots catalogue has a lot of info. I generally stick to the same ones if possible- Big Bad Wolf, Bloodsuckers, Dragon's Luck. I'll use Gonzo's Quest if I have to. I don't really like the high variance ones.
I never pay any attention to the paylines. Just use the max.
If you have a lot of wagering to do, you could try a few different slots. That's how I learned about a some of the slots, wagering a few thousand on 888casino. I did some on Gonzo, some on Big Bad Wolf, some on Bloodsuckers, a bit on Decco Diamonds, Egg-o-matic and Jumanji. You find out which ones you like.