Joe- This time of year I employ two main tactics. First, I will target deep grass beds. Particularly ones that grow all the way to the surface. Fish the edges and the holes in the grass at various depths. ( I like a slip cork with the string and bead stopper) Second, I will drift oxbow lakes, slews, and deeper tribs with two or three rods at various depths until I locate where they are suspending.
Use very limber rods so that you don't tear the hook out of their mouths. I use old fly rods with small underspin reels. I always use a jig head whether fishing with minnows or artificials. Also, try using minnow tipped tube jigs.
Crappie can be very finicky, so don't give up on an area until you have tried every depth, color, and combination in your arsenal. Trust me when I say it can change day to day, or even hour to hour with frontal conditions.
BTW- If the flow has flathead cats you can almost always forget finding crappie in the deep bends of the main river in the winter. Those big flatties will be stacked up there in hibernation mode and crappie are too smart to hang around!