Confidence.
The problem isn't that you can't read the sonar. It's not that you can't fish. It's not that you don't know where to look.
Your problem is that because you aren't confident in your skills of reading the sonar, and that you do not put confidence in the data given, you go back to your old ways. You are given pieces of a puzzle. Its just up to you to put them together.
It took me awhile to do the same thing. If I didn't see fish on my graph, that was ok. I still stopped and fished. haha
That type of fishing is fine for resident fish. You will still pick up a few on a jig and worm that stick close to that area and feed in that area.
But when it comes to schooling fish, fish that roam and actively feed on shad, thats what you want to use your graph for when your searching for the "archs". If there are no shad then there will be no bass FEEDING ON SHAD, point blank no ifs ands or buts about that.
But you could still catch a few holding to the bottom or the nice drop off that you find. Thats excellent!! Use your graph and find more areas with the same type of drop off and fish them. There is no reason to probe the point from 0-30ft when you consistently catch fish on multiple 12-15ft drops near deep water.
I also started doing something the past few years that have helped me out a lot.
SSSSSSSSSSSSSSS vs ---------------
Imagine a boat graphing a point using the two different paths above. One S'ing in and out from 6ft-18ft back from 18ft-6ft, and the other making a single pass at 12ft depth.
As papajoe said above...you are already viewing a small portion of what is directly below the boat. So, increase your viewing area. You have more ability to see:
bottom hardness
active fish
shad
drop offs
brush piles
etc...
If none of them things are located in your quick straight pass at 12', then you would just want to move on. But if you found any, all, or even a few in your S passes, you can start putting together a pattern. Once you keep adding pieces together, eventually your puzzle will all be complete. In a matter of hours you will know the fish are targetting bait balls, while suspended in 12-16ft off clay humps with deep water access. But you have to single out certain things before you can develop and realize what is going on. Thats where the confidence in knowing and believing in what you are doing and what you are seeing comes in.