A fishfinder with a good verticle jigging mode has helped more than anything to understand the mood of the fish. Even when i will be casting I will drop a jig straight down and watch the screen to see the reaction. In most cases there will be fish down there, not always crappie, but even a bluegill will show some hesitancy at the same time a crappie will. If a fish rushes the jig, pauses a second then grabs it im good to go. If they pause, swim away, come back after a few lifts of the rod then barely lip the bait I know what kind of day its gonna be and change my jig weight or slow my retrieve.