If you are looking for BIG cats, carry a heavy rod, use a big hook, and use live or cut bait (like Dawson said). Drop it to the bottom in some deep water and let it sit.
If you are trying to catch some general cats, weighing a couple of pounds, I always toss on a piece of hotdog. They seem to LOVE IT. I guess is the salty/oily makeup of the food. In this case, the pole and hook don't need to be huge, but I'd still recommend at least 20 pound test and rod.
Cats are almost always good fights! Have fun!