I suggest you have a good knowledge of the waters you are fishing. If you are looking a body of water the simple answer is to look at where you caught them in the spring. Reservoirs that have many coves off of the main channel seem to be popular spots. Chose lakes that have deep areas where the fish rest but have shallow areas with active plant life all year round.
Crappies are going to look for bait fish and those bait fish are going to be found eating what they eat – plants. I know its winter, but as long as the water holds nutrients and there is some light plant life will continue to grow and this is where the crappie will be looking for food. The ice that has the thinnest layer of snow will let the most light through and this is where the plant life will be found. Don’t forget that when the light shines through the ice it melts from the underneath and will be deceptive on how thick it is. Compare these areas to the known ledges of the lake and fish the areas where there are ledges with plant life and fish right on the shadow edges and right at the entrance to the plant life.
Now that you know where to put your holes, Let us cover a couple other things depth finders, temperature gauges and even cameras. There are many depth finders out there you can find some that need to be in the water and some that will slide along the ice and these all range in price just as their functionality does. Some of the lower priced depth finders need their sensors submersed in water so drill small holes and test the depth. I’ve used large wood auger type bits with extensions and a cordless drill to have a quick method to test the depth it leaves the ice in good condition if you don’t like the spot. After you got a test hole you can quickly drop a temperature probe down and look for warm waters.
Warm waters are good to find because this is where the fish will want to hang out. Also warmer waters mean that the fish will be more active. Granted these waters are still cold so they are not going to be really active. Good news though these fish are still hungry. But remember that everything is going to be moving slow down there, bait fish included so avoid quick movements.
Finding the right spot still can be hard to locate. Here is a trick I learned a while ago, although you might get a good beating for it, I show up early and look at previous holes. You can tell how successful a hole was by how the snow and ice is arranged around it. Crappie will tend to roam around the lake some so don’t drill where other holes were but follow a line that may be evident. Remember to stick to the ledges in the water structure or edges of plant patches.
One area I found successful year after year was a cove that had shallow waters that gradually sloped to a depth of 18 to 20 feet in the center. This is where we always sunk a few bales of hay or Christmas trees every fall. The plant life seemed to cut off at about 6 feet of water. This was a great spot for crappie throughout the year.