Give you a example of fishing a few mornings ago. I started out where I previously caught fish. Depth finder showed fish but few bait balls as I crisis crossed a river channel. Depth of river channel was 15' and depth of the lake above the channel was 10'. After 30 minutes of just hitting one dink turned and headed towards deeper water. Went about a half mile upstream in the lake and the bait balls got thick on the depth finder, hitting the sides of the channel as river now was 20' deep filled with bait balls, we started hammering the fish. They were in another quarter mile length of River channel along the sides around bait balls in 12 to 15' of water depth about 7-8' down. Covering water trolling jigs and cranks watching the depth finder is part of my strategy in finding fish the crisscrossing and covering the area changing colors, playing with depths the baits are running is the other half. As the water gets hotter, fish will move. Not far,,but they seek their comfort zone and all the different kinds will be there as well as we caught 5-6 diff kinds of fish on cranks besides the crappies. There is not much cover in the lake we were fishing, so I look for bottom irregularities like secondary creek channels intersecting main River channels, humps, droppoffs, possibly old stumps or rocks next to channel edges, things that might also attract them as well as long slow dropping points near deep channels and water. Bait balls are a definite to work thru. Learning to read structure on a fish finder is key to finding fish for me as I end up nowhere near a bank most of the times. If I find cover, I work it thoroughly also. The depth finder becomes my eyes as I also watch the surface for feeding fish or bait movement. I still study paper topo maps of the water I fish even tho I use the map cards on depth finder as I find them more detailed and the older the map, the changes in the bottom features I mark with ink pen, as they change with time. The older paper maps can still be found sometimes in the smaller out of the way baits shops if you run across one now and then.