I'm doing my darndest to raise a child who is not picky. DH is not picky at all. In over 2 years I've only made maybe 2 dishes that no one liked. I call those lessons learned. With DD (she's 4) we keep it simple. She gets an age appropriate portion. I do keep track of her likes and dislikes so that she gets slightly larger portions of things she likes and slightly smaller portions of things she dislikes.
If she complains about the food or gets overly pokey about her eating, we give her more. For example, I made beef fajitas earlier this week. DD doesn't understand how to eat a fajita yet (plus, her mouth is still little), so I gave her some of the meat filling (did not give her the bell peppers b/c I know she doesn't like them) and gave her extra salad and cucumber slices. She ate all her salad and cukes, but was bemoaning the beef. I finally gave her 3 more pieces of beef (about the size of a dime) and said, "If I hear one more complaint or if you continue to play games when you are supposed to be eating, I will give you 3 more pieces to eat." She finished her dinner without another complaint or problem.
I'm very fortunate that this is a rare occurrence in my home. DD loves vegetables for the most part (just the bell peppers that she struggles with now). She likes beans -- especially things like bean soups when you can sprinkle some shredded cheddar cheese or parm cheese on the top. Like any kid, she loves pasta!
I think the biggest problem we struggle with is that I make very limited side dishes. I stick to potatoes, sweet potatoes, salad and cucumbers, carrots (in various forms), brown rice, pasta, zuchini and yellow squash (spring/summer only), bell peppers, green beans, tomatoes, broccoli. I realize this is better than a lot of families, so I'm grateful for that. Sometimes it just seems redundant is all.