How I've helped guide my child to eat well:
I buy only what I feel comfortable with him eating. We talk about foods, what's a protein, what's a carbohydrate, what's going to fill you up for longer (steel cut oats with raisins and a good protein) and what's going to make you feel lousy later on.
I let him choose, a lot. "Go to the fridge and pick out a two veggies you would like on your plate. Okay, now wash them. Here's the cutting board and a (age appropriate) knife-- why don't you cut them how you want them to look on your plate?"... "Find a protein for your plate. There are hard boiled eggs in there and there's some veggie sausage." and on. I don't let him choose everything, but I do offer choices to him in areas where he complains.
I let him have things which work for him. For health reasons, I need to cook my veggies. It's great that Kiddo loves them raw. I don't dictate HOW he eats them. He likes his carrots just washed with the skins on, ends trimmed. He likes to eat the snap peas from the yard -- but only the pea part. I'd rather he keep those things in his diet instead of telling him *how* to eat them and him refusing them altogether. "How" choices can really be our friends-- even letting our kids pick their dinnerware or silverware can make things feel better for them. My son regularly will pick the long-handled iced tea spoons over a conventional one. It makes eating novel and fun for him.
In our house, we treat eating as something which should be nourishing to everyone. I might make a stir-fry and leave his veggies raw, serve the rice on the side and offer the protein in a portion he can enjoy.
We also know that there are favorites and do offer them in limited quantities. When Kiddo was three and LOVED macaroni and cheese, we decided to buy one box a week and to let him indulge as much as he wanted. At even six, we could make up a box which would then last all week-- he was so secure that he could have his favorite dish that he focuses more on the veggies. The other day he asked me if he could "not finish" the pasta because he wanted to eat his carrot.
People are right that eating well is a personal thing. I grew up being forced to eat certain foods, and frankly, it was such a violation of my self. It's ruined some very good foods for me as an adult. Even when I was gagging and throwing up, I was again and again forced to eat foods I hated in order to have seconds. It's because of this, and because I have studied HOW a child learns to eat well-- some foods, they must taste many, many times before they decide they are safe; this is biological safeguard:
http://www.babycenter.com/0_how-to-handle-a-picky-eater_6...
One of the small victories in my life is that I have actually worked myself up to eating half of a salad before my gag reflex started to threaten me. This, when I was in my late thirties. It's sad that some foods were ruined for me.
The foods where small exceptions were made (the tuna casserole with no onion, separated from the 'contaminated' onion part by toothpicks--- that was love to me), I can still eat those and now LIKE many of the foods that had previously been omitted. I also have a tongue which is pretty savvy on flavor and as a kid, some flavors were very, very strong to me, or the texture was off-putting.
My son eats well because I trust that he will grow into a person who eats well, all on his own. I trust that his palate will develop and become more sophisticated, much as my own did. I don't want to ruin any food for him, so I limit the super-desirable, less healthy items and let him make plenty of choices from what is good for him, in a wide variety, as is appropriate. It's such a little thing to say "yes" to on my end, and thus, it's not such a big thing for him.