Couple things I've found trapping rats.........
1. a trap that has caught one and it leaves blood on the trap out traps other traps without blood on them.
2. the absolute best bait I ever had success with was lasagna. Two at once....and multiples in a couple hours. Like they didn't care if they got caught.
3. put trap under a half box like a carton used for can goods, pop, etc. Cut out doorway on one side. make sure tall enough for trap to work, although the plastic teethed push opens work well under a box. The box creates a dark space and they feel more comfortable eating. Perhaps the darkness tends to suppress the looks of the trap...who knows.
For what it's worth..........
"By the time you realize your father was a smart man, you have a teenager telling you just how stupid you are."