I've always had success with catching a small fish in the same area (almost always bluegill for me) kill it and puncture the air bubble with a knife so it'll sink. Hook it firmly and cast it out as far as you can. Place rod in rod holder with reel set to allow unwinding and wait. I've rarely failed to catch one this way and multiple setups increase your chances.

I think using the small fish from the same area is the key. They're already familiar with it and finding a dead one on the bottom they don't hesitate to gulp it down.

Oh also when a catfish takes it give it time to swallow it completely before giving the rod a yank. You're gonna eat him so no biggie with swallowed hook.