Some strategies. Visual cues: smaller plates, don't put serving dishes on the table, don't leave food where it can be seen. Adults can show they limit themselves to single servings. The family can eat in the dining room or kitchen, not in front of the tv. When your child asks for extra food, distract with toys or activities, or say that he/she can eat a little later. Ask all caregivers to respond the same way.
Offer healthy foods. Offering healthy foods for meals and snacks allows kids to eat really as much as they want. You can't really go overboard on carrot sticks and celery with yogurt dip! At mealtimes you can help them divide their plate into quarters- 2 quarters for veggies, 1 for meat and 1 for starch. This helps them begin to learn portion control.