A lot of us like soft plastics or hair/feather jigs during winter. You can find a lot of quality jigs made by guys on this site. Most of tightline when it turns cold since crappie aren't as active. Bobby Garland plastics and panfish assassins have always done well for me. Try a variety of colors and the fish will tell you what they want. If your fishing deep or stained water, you might want to try some of the glow baits. They are especially good early and late in the day.
You need to use a jig heavy enough where you can feel it bumping around in a brushpile. If you still can't, you might want to add a lead sinker either above or below the jig. This time of year, many of your biggest crappie will be very light biters.