There are various laws governing the use of trotlines depending on the states in which you intend to use them, and it always pays to know in advance exactly what those laws are. Rarely does the excuse that you 'didn't know' hold much water with the Game and Fish boys, and it can keep you in their good graces if you know and obey their regulations. In many areas, fishermen who are not fishing for commercial purposes may use 25 hooks on a trotline.
One of the best things about fishing with a trotline is that you do not have to stay right with your lines all the time. This is particularly good if you are fishing for the sole purpose of bringing food to your table. You can set out a trotline and leave it while you spend the night at camp, then you can get up in the morning, catch some bait on the way to your lines, when you get there, pull your lines in, rebait them, and have fresh fish for lunch when you get back to camp!
The most common trotline catches are catfish, crappie, and, if you like them, turtle. Just be careful, because some of these turtles are snappers, and sometimes you pull a good sized gar or even a gator out of the water, and you have to be prepared to deal with that situation safely when it happens.
When you are using a trotline, you can go from one side of a channel to the other with your line and hooks. That way, any fish passing through are likely to be able to come into contact with your offering and be tempted into taking a bite. What you do is just bait your hooks and then stretch your line from one side of the channel to the other, tie it off securely to something stationary on each side.
Trotlines will work well in ponds and lakes as well. One thing you have to remember is that you will be getting someone tangled up in your line if you are not careful, so it pays to know the areas in which you plan to set out your trotline, know the regulations in that area, and behave accordingly. If you are putting out your trotline in a lake or pond, you can easily weigh the end down with a brick or something else sufficiently heavy or tie off to a tree. Just remember it will be dark, so you might want to mark the tree to which you are tied, or mark your cord somehow so that you can easily get back to your line in the dark.