You can increase your success rate of hooking up on wintertime crappie by understanding what technique to use depending on the water and the weather.
Windy and/or Cloudy
When the water visibility is broken up by either wind and/or cloud cover you can effectively target fish from directly above them. Use your trolling motor to stay positioned directly over suspended fish and vertically jig. Put a piece of split shot 6-12 inches above your jig to keep your line straight without compromising the jig's action. During the winter fish are lethargic, so let the jig sit idly at your desired depth and occasionally pop your rod tip upward without reeling and let the jig fall back down. The current in the water will create subtle action to your jig making this "dead sticking" approach the most effective at this time of year.
Calm Water and Clear Sky
When the sun is out and the water is clear and calm, the crappie bite can be finicky. Don't park your boat directly over where you are targeting fish. Stay 20-30 feet away from your target area and cast to that spot using either a slow pause and pop retrieve or a slip-cork retrieve. Slip-corking is typically more effective because it allows you to accurately reach your desired depth and stay in the strike zone longer.