What you will need to catch catfish..

First, to catch catfish legally, you will  need a fishing license and to have read your state's Freshwater Fishing Regulations. Check your local laws about setting and labeling trot lines and the minimum size fish and species you can keep. Some states do not allow trotlines at all or restrict the number of hooks. The easiest way to get started is to visit a local discount store and buy a pre-packaged trotline with the easy clip on leaders. These allow you to string the line between two points along a lake or river and then come back along it and clip on the baited leaders. These will handle fish up to 14 pounds or more but if you are fishing for monsters then make your own trot line along the same lines but with heavier line and hooks.

Of course you will need a boat of some kind to catch catfish on a trotline. It might be a $30,000 Champion or a $200 rowboat.

I personally fish out of a "sit in" 9 and a half foot fishing kayak. It allows me to get up into creeks along the lake and uses no gas.
Go down to your favorite body of water and scout for ideal spots. Look for deep pools located just after gravel bars, which are free of stumps and trees, mouths of creeks.  Avoid shallow muddy stagnant areas when trotline fishing for catfish. You'll end up with a bunch of turtles on the hook. Catfish are bottom feeders so you'll need a heavy weight of some kind to get the middle of the trot line submerged.

Know the length of the entire line and find a spot between two limber, green trees (at least 1" diameter) and tie off the line just above the waterline to a sturdy branch that will also flex. Start paddling and reel out the line and attach it to the tree on the opposite side of the fishing hole. Allow enough slack so that when you add the weight it will sink to bottom but not so much that the two ends will float up.

You can also set a trotline for catfish from a fixed point on shore sloping along the lake or river bottom to a weight on the bottom with a float above it on the surface. Trotline fishing for catfish is not an exact science and you can modify the trotline to work for the area you are fishing in.

Trotline Bait for Catfish

Finding the right bait is the key. There are dozens of brands of blood bait, stink bait, etc that claim to be the ONE. I have never had any luck, at least where I fish, with store bought recipes. There are recipes on the net for catfish and carp bait you can make yourself. Beef liver and frozen bait shrimp are always good choices in my fishing hole.

Live shad or small perch are excellent bait to use on a trotline to catch catfish. I usually mix up the bait, alternating a bloody bait like beef liver with a live perch.
You can pre-bait your leaders with the blood bait, etc, but you will have to wait and put live bait on at the last minute. Check your lines as  often as practical,  but not so much that you are spooking the fish away. I check my lines at least twice a day.

The earlier you can get  down to check  your line the better since the catfish will be trying extra hard to get away when the sun comes up and when it would normally be deeper in a hole. Make sure you keep only legal fish. There are size limits in almost every state.

There are many good stink baits and blood baits for catfish available online and at discount stores. You might start with one of these and then try your hand at making your own recipe,  which can be fun but messy, do it outside of the house, of course or your wife won't appreciate it very much.

Kicking Back At Camp And Catching Catfish the Easy Way                                          

One of the best memories of my childhood was trotline fishing for catfish with my father and uncles. We would set up camp along the river and set out several trotlines. Back then there were no laws limiting the number of hooks you could set. My dad and uncles would set up to twenty trotlines with up to fifty hooks each. We would build a big campfire and cook supper right after setting and baiting all of the lines. We would wait a few hours and then go and check the lines for fish. On more than one occasion we pulled up monster catfish, weighing over fifty pounds each. There is always the suspense of not knowing just what might be on one of the many hooks when you see the branch that the line is attached to twitching and pulling into the water. Most often it will be catfish but occasionally you might hook a large freshwater carp or alligator gar. On one line with thirty baited hooks we once pulled in twenty five catfish. the hooks had been baited with "stink bait" made from chicken blood and flour dough and a host of other secret ingredients that only my uncles knew of. What makes trotline fishing so fun is experimenting with different baits and trotline rigs to find out what works in your area.