Mine are 11, 4, 3, and 19 months. My oldest is the picky one. We finally set up a schedule where if she will eat what I make for 4 nights, she gets to pick what we have on the 5th night. I also make sure the foods that I cook arent way out there. Like vegetables around here consist of peas, green beans, and corn. We splurge and have icky vegetables when the rest of the meal is what she really likes
I also have the rule that you tell me what you want on your plate and how much but if you dont eat it all, you dont get dessert. I am against adults making kids' plates with this rule as it can lead to overeating. For a small child, a tablespoon is a serving so I would pile way too much on there to expect them to eat it. They say "when" within reason and they eat it all.
I also have a rule that they have to have eaten a certain portion of the meal before they get a drink, That may sound cruel but my kids will fill up on Koolaid and then not want to eat only to be hungry an hour later.
My picky eater really is liking the idea of picking what we eat and she is cooperating more now. Good luck to you and I HTH