I do not hunt possum and coon much. But, I have hunted a few. Always at night between 10-2 is when I see the most. I know it sounds stupid, but, get some left overs you dont want, or that is old but still in the fridge. Heat them in the microwave for about 3 to 5 min., till it gets hot and smelly, then just toss them out in the field or low light area. Just anuff light so you can see them. Sit in your car, or out your window, or where ever you have a clear shoot and good cover. They will come. They always come. Hell, you might even luck out and get a yote come in for a bit. It may take a few hours, but the coons and possum will show there face.
Dave.