Set a good example. Don't make disparaging comments about foods you dislike.
Kids have small stomachs.
Small meals with snacks in-between are easier than three big meals a day. Don't pile food onto their plate. Children thrive on routine. Keep mealtimes regular and, even though its boring to you, serve them the same meal a few times a week with some variation, once you have hit on something they like. Usually they end up disliking it intensely.