The first thing i try to find is the green weeds. Fish will be in the green weeds for oxygen and food year round.
After that, you can look at the breaks to the main basin and drill from shallow to the deeps to see if fish are holding to a certain depth. The crappies will likely be suspended in these areas during the evening bite.
Many times you can find crappies and bluegills mixed together. Crappies will often be higher in the water column compared to the gills.
I look for basins, then a shallow feeding shelf, I fish the same shelf for both, but seem to get into them at different times of the day. I focus on the transition and drill plenty of holes to hole hope.
I like to start by looking at a contour map of the lake if I can find one. I look for flats that are formed where the contour lines widen out. some time these almost look like a gradual point coming out of the contour change. also flats that have the sticky bottom will hold the bugs. as they rise off the bottom at night it tends to bring in the crappies more so then the bluegill. this leads me to my second spot I like to look at and that is the outside bends of where the contour bottoms out at its deepest point and forms a bend up to 90 degrees. also look for underwater points, especially ones that don't really stand out much. just that slight little bump can be like a magnet to fish. I see this on this one lake I fish. this same lake also has another thing that not all lakes have and that is a double saddle area. this area has held fish in the past for me. one last place I like to look for is areas where there is a under water island by either the shore or another underwater island and it forms a channel or canyon type of area. think of it as a under water funnel point where the fish have no choice but to swim through there to get from one place to another. I hope how I wrote this is easy to understand. it would be easier to explain if I had a way to copy a picture of a lake map on here and mark some examples of spots I would check.
Here is a link to a different forum where I included a lake map with areas circled to look for crappies on this particular lake. it is reply #8 in this thread. this might explain it easier if you look at the lake map I included.