I could be wrong but every time out, different conditions water level, etc. I just start fishing around brush and trees, even a flasher (old school) will show you that. You don't catch a fish after a few minutes move on. Bridges are usually good (Shade). So getting a GPS location is not always a ticket to success. Just start figuring out a pattern, how deep are they, you have to know how deep your lure is so when they eat it and you catch one you know. When I started off fishing I kept a log book on everything, really helped me figure some stuff out and I fished one lake to learn that lake. Catching crappie in the heat of summer in New Mexico is difficult at best, in Texas, well you see the reports. My guess is that the eco-system in Texas lakes produce many more crappie than the eco-system in New Mexico lakes so finding those crappie is tougher but when you do. I like the idea of sinking brush, just that process will teach you a lot. Where to place the brush and how does it hold fish. I found Ernest Patty's Crappie 101 dvd a very good investment as well.
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"All that we call human history--money, poverty, ambition, war, prostitution, classes, empires, slavery--[is] the long terrible story of man trying to find something other than God which will make him happy." — C.S. Lewis