The National Shooting Sports Foundation just released another of their shooting tips videos. This one features Ryan Cleckner who was an Army Ranger sniper team leader in an earlier life.
As Cleckner makes clear, you can't always shoot from the prone position and you rarely have a shooting bench when you're out in the field. He discusses and demonstrates a number of alternate rifle shooting positions including two sitting positions, kneeling, and standing using a tree as a brace. With many Southern states starting their deer seasons as early as next month, this is useful information.