How to read Navionics/Topographic maps effectively

Flats aren't always the graveyard that everyone thinks they are. Certain flats,(if they're situated between two other structures that aren't too far apart) can hold a lot of fish. It also depends on the type of fish and what they're eating. In one lake I fish for lakers,there's a 50-60' flat that's pretty large but it's between the main deep part of the lake and a slightly deeper, fairly large bay. The lakers cruise across it in packs like wolves on the hunt for smelts and herring. We set up right in the middle of the flat and spread our lines out to cover water, you might not see anything for a few hours but then all of a sudden there'll be a half dozen lakers come through and we'll catch a bunch, then maybe an hour or so later it repeats itself. Also, in heavily pressured areas, the fish may move off the "sweet spots" and cruise a big flat when there's a lot of noise from fisherman. If you find the right area, you can have them all to yourself. Just takes time and a lot of trial and error before you find the right spot.