Using Your Hand to Estimate Your Portions
1 cup = your first
1 ounce = the meaty part of your thumb
1 tablespoon = your thumb, minus the meaty part
1 teaspoon = the tip of your index finger
1 inch = the middle section of your index finger
1-2 ounces of a food like nuts or pretzels = your cupped hand
3 ounces of meat, fish, or poultry = the palm of your hand
via Use Your Hand to Estimate Your Portions, [Lifehacker]