Ok, here goes.
Hard bottom is the single most important feature for offshore fishing. Even when fish are on points, ledges, piles, etc, they will use hard spots on those features. A brush pile that is sank in muck will rarely if ever be an effective pile, while one on hard bottom may hold fish year round.
Finding hard bottom starts with with looking at your map. Most hard bottoms on Toledo can be found on the north side of a main lake point or ledge. I think thi is due to water current flowing north to south, washing the muck off of the north side of stuff creating hard spots. In creeks, start on the inside edge looking for hard bottoms. The current running from the back to the mouth creates hard spots on the inside of the structure.
Creek bends are also prime areas to find hard spots. Outside bends typically will have hard spots.
Dont overlook roadbeds either. They seem to be better fall-spawn, but they are highways (literally) that fish will use to travel and feed on. Crawfish love gravel and roadbed fit the bill perfectly.
Once you have found areas on a map, idle them with SI and look for bright spots. Hard bottom has a hot return and will appear much brighter than mud. On you sonar, a hard bottom will show a much thinner line. Mud bottoms will be thicker lines due to your sonar penetrating the mud. I can say that I catch 90% of my fish on areas that have hard bottom.