Here are some great tips from Weight Watchers on eating out and portion control:
Divide your meal in half. As soon as the plate is set in front of you, ask your server to wrap up the other half to take home. Doing this right away helps you avoid the temptation of eating too much just because it's there.
Consider ordering from the appetizer or kids menu. Portions are almost always smaller. Also, restaurants will often make half portions or lunch-sized portions at dinner time, if asked.
Use your hand to measure the actual amount of food on your plate.
Here's how:
Your fist is equal to one medium fruit or one measured cup
Your palm minus the fingers is a 3 ounce portion of cooked meat
Your thumb (whole thumb, from tip to base) is equal to one ounce of meat or cheese
Your thumb from the tip to the first joint is about 1 tablespoon
Your index finger from the tip to the first joint is about 1 teaspoon
Hope this helps!!