I started my kids on veggies first, when they were babies. I don't know if that's the reason, but they love them now.
I usually serve a veggie tray while they're waiting for dinner to be ready and they munch on that. Sometimes I'll steam some and put them on the table too. I don't mind so much if they get full on veggies and pick at their dinner. I do mind if they get full on sweets and pick at their veggies
, so veggies come first.