In my experience, round mud crab traps are definitely the way to go. The theory is, the bigger the tide the more activity and a good rule of thumb is to set your pots around the full and new moons. The other thing to look for is a creek or river flush brought on by seasonal or rainy weather.
You can use fish frames to lure them in but I’ve seen any number of weird and wonderful baits over the years….and they’ve often worked! The crabs find their way in through openings in the trap but then can’t get back out the way they came in.
One thing to remember is that crabs love mud so remember to drop your pots where it’s muddy, not sandy, so somewhere like in or at the front of a drain is a good idea. Remember to tag your pots and read up on the take limits for your local area. Now you’ve caught some crabs learn how to cook them here.