- Who wants to weigh foods to practice portion control? Certainly not me!
 - Cereal (1 c.) = a baseball
 - Salad Dressing (2 Tbsp.) = a shot glass
 - Nuts (1 oz.) = a cupped palm
 - Cheese (1 oz.) = a ping-pong ball
 - Lean Sirloin Hamburger (3 oz.) = a mayo jar lid
 - Peanut Butter (1 tsp.) = one die
 - Beef (3 oz.) = a bar of soap
 - Rice (1/2 c.) = an ice cream scoop
 - Potato/Sweet Potato= a computer mouse
 - Butter (1 tsp.) = a Scrabble tile
 - Fruit (1 c.) = a tennis ball
 - Cooked Pasta (1/2 c.) = a golf ball
 - Fish (3 oz.) = a checkbook
 - Chicken (3 oz.) = a deck of playing cards
 
In order to keep your "guesstimated" portions in check (I doubt there will be a food scale handy when you sit down to eat) you can use everyday household items as a mental reference guide.
Here are some examples of standard serving sizes: