First off, find some clean water to harvest from. Crayfish do not tolerate polluted water very well. Secondly, they are primarily vegetarians but will feed off living or dead organisms. You can use fish, chicken, dog/cat food, old freezer meat or just about anything that is kinda smelly. I like to get my fishing fix by catching some squawfish/pikeminnow, cutting them into chunks and placing some in my traps. If you know of anyone that has some property with a creek running through it, ask them kindly if you can harvest from the creek and share the bounty. I can fill 3 traps in just a couple hours with fat crawdads. Best part is, you don't even need a license. I do recommend only keeping the larger ones for the best meat and for conservation purposes. Shoot for 6" min.