Mix new greens such as kale or collard with romaine lettuce in a salad or chop greens quite fine for a stir-fry or pasta sauce. Add new veggies to a bean and vegetable taco. Condiments like soy sauce, catsup, salsa, mustard, relish, and pico de gallo add customary tastes to new foods. Use a favorite salad dressing or even salsa over cooked or raw vegetables. Use vegetables for dips such as hummus or salsa.
Oil makes foods taste good.
Add extra olive oil at first, cutting back gradually. You eat it, too. Don't try to persuade a child to eat something you won't eat. Eat with enthusiasm to let your children know you enjoy the new food. Talk about the new food while you are eating it.