Take smaller bites. When you're eating, try to avoid putting large bites into your mouth. Instead, divide your meal into more morsels. This forces you to eat more slowly, which in turn can stretch out your meal and make it easier for you to identify when you're full.
Divide up your food before you eat. Cut meat into small pieces, or break bread into tiny bites.
Use smaller utensils and smaller plates. If you tend to eat your cereal with a large tablespoon, swap it out for a smaller teaspoon. A meal looks like much more food on a lunch plate than a dinner plate.