Avoid sitting in one spot and spinning your tires. This only heats up the tires and digs you in deeper. If you have standard differential, without traction control, it will be possible for one wheel to spin while the other is motionless. A burlap bag, grocery bag, or cardboard carton under that spinning wheel may get you going. A little under the tire may provide assistance for a spinning wheel.
Sudden moves cause trouble when the traction is poor.
Try to avoid going up a hill right behind another car. If it loses traction and starts to slow down, you're licked, too. When approaching a hill, follow the other car at a significant distance and then pick your own pace and maintain it. Inertia is your friend while going up a hill with poor traction. If your drive wheels start to spin or slide while going up a hill, ease off on the accelerator slightly and then gently resume speed.