Limit their snacking
I do not allow my children to just grab anything out if the cabinet. The only exception is fruit. They can eat that at anytime. If they wanting more than fruit than I can fix a nutritious snack and they will be hungry enough to eat it.
Also if snacks are limited and controlled when it is time for dinner they are more willing to eat what is put in front of them and a healthy meal is easier to present then.
Also just before dinner is ready I put out a tray of raw veggies for those who are starving and is having a hard time waiting for dinner.
Also keeping a container of water that is easy to get to in the fridge or out where they are playing helps them to drink more water throughout the day.
mom to 7