Wrap a large beach towel or some such around the trap. This helps capture the smell of the "bait" making it a stronger scent inside there.

Cover the floor of the trap with newspaper, so his paws are not feeling the wires. Put slight bits along the path he enters, like a "Hansel and Gretel" trail, with the bowl full of bait at the back. Do not put any bits where his front paws may trigger the trap but he is still halfway out the back end. (Yeah, I've done that! )

Use salmon as someone mentioned. Or tuna in OIL, NOT in water. The oil helps with the aroma.

Good luck!