Rigging your line
The 2lb test attached to the sinker is there for a reason. Often you may be fishing on rock structures where the sinker can get caught up. If you catch a fish and your sinker gets snagged the 2lb test will break allowing you to reel in the fish. The length of 12" may be increased with faster water currents. I choose 20lb test because of the many large ones that have gotten away. Also, the catfish eye sight is poor enough not to notice the 20lb test.
A Bit on Bait
Often I will use chicken liver. Other species of fish may eat the liver but it is less likely than with worms. Minnows work well. I usually will catch blue gill or small shad and use this for bait. Blue gill are most always hidden among rock stuctures. I usually just drop a fly line with a small nymph to catch one. You can place an egg drop sinker in front of the hook and attach the fish behind the dorsal fin.
Chumming
Chumming is a technique to bring the catfish to you. Catfish rely on their keen sense of smell when hunting for food. This works by throwing out finely ground up particles of "food" where your fishing. Hopefully this will draw the far away fish to your baited hook. The food can be any of the following: cat, dog, dough bait, ground up fish pieces from your last catch or commercialy prepaired chum. If your stream fishing it is best place the food in a coffee can with holes cut in the side. Place this just upstream of your baited hook.
For great catfish recipes click here: Catfishinstitute