My brother and I won a tournament this weekend on Green River Lake basically fishing ledges or some people call them drops. A carolina rig is a good way to feel the bottom and tell what the bottom is composed of. One of the best ways to tell which ledges have fish is to idle over them with your sonar. If you don't see any fish then move on. My favorite bait for fishing ledges is a deep diving crankbait because you can cover a lot of water and big bass like big crankbaits.