My trick for feeding my daughter has been copied by people who saw me do it and I thought I would pass it on to you.
When she was young (She's 15 now), she would say that she was done eating and I would say "Let me check" and I would lightly start pressing her stomach with my finger tips. I would "Find" spots on her and say "Oops here's an broccoli shaped empty spot" and pointing to a different spot on her stomach "The spot could hold some more bread, but then you would be full"
After a couple years of this my daughter started feeling her own stomach at the table and saying "OH! heres a bean shaped empty spot" and she'd eat some beans.