What leglifter said.
Large bait (Muskrat, Mink, Rabbit, Squirrel, Deer scraps) wired down.
Also lure. Lure will have more calling power, but they want food this time of year (or any time of year)
When using live traps always stabilize trap. Use stick, stone, corn stalk to keep trap from wobbling.
Dig depression under the pan and place some bait/lure there also. When trap is set in place, there will be bait that they just can't get at without firing the pan.
Set live trap on location. Location, location, location.
If the boy uses foothold traps....
Have him set one or two foot traps to the side or back of trap. Blend in trap. This is a 'blind set'.
Often a critter circles live traps. Often the critter doesn't enter, just circles. This blind set will solve that problem and keep life interesting.