SI is the easiest way to find them. I usually start by scanning around docks, since the owners have usually placed them already. On certain docks, a good indicator is rod holders.
Another good indicator for docks is fish feeders.
As to finding them. Start with sharp points near channel swings on Main Lake at 10 FOW. Run a sweeping pattern across the top of the point overlaying side-scan to your map. Slightly overlap and work your way out to 25 FOW. If you record your track, it should be clear where they are. Once you find one, repeat in similar locations across secondary points.