All of my children at one time or another have suffered from picky eater syndrome. I take full responsibility for this. I did not have food philosophy when they were young and quite frankly my cooking has improved dramatically with age. By food philosophy I mean that I did not have a plan on how to handle the family table and the situations bound to arise during meal times that would become habits. Even if those habits are unintentional. An unintentional habit for me was that I would mentally note which things my family liked and would make a point to serve those foods on a regular basis because I like to please them and do not like to cause stress at the meal table which is supposed to be a time to relax with one another. Granted we have a large repitore of things that my family enjoys but you can have twenty favorite meals and still be a picky eater.
Children do out grow picky eating. My middle daughter Emily recently decided to like salad because she is old enough to be at present at other families meal tables and salads are frequently served. She wants to be a blessing as a guest not a picky eating. I am very proud of her for this. My oldest daughter discovered many new foods simply by spending many of her entertainment dollars eating out with friends. My son, who makes gallant attempts at liking new things really does not like new things. And, after all these years I finally have a food philosophy.
Feed them what they love, make meals special and joyful, and occasionally throw in something weird just for fun. Include them in helping to make the new food. Make that part of the meal fun and move on.