If you don't catch a mouse in the first few nights, the trap is in the wrong location. To help rats overcome trap shyness, place traps unset, in place, for several days. This allows rats to overcome shyness and results in better catches. Baited traps rely on the rat's being attracted for feeding. The bait must compete with other available foods, so no one bait is ever the best bait for all locations.
Rodents living on garbage or spoiled food prefer something fresh.
Raisins or grapes for roof rats. Sardines packed in oil for Norway rats. Dry rolled oatmeal is excellent for mice. Gumdrops for mice. Traps can be nailed to rafters and beams to take advantage of areas where rats travel.