1. If at first you don't succeed, try, try again.
My children haven been offered cherry tomatoes weekly this summer from the garden. After a number of weeks, all of a sudden one son became obsessed with them! He LOVES them and can't get enough of them. It's a good reminder to keep offering your children food items that they turn their noses up at initially. Someday they may like it!
2. Remember the toddler-ability factor.
When we eat soup, for instance, my toddlers have a hard time keeping the liquid on their spoons in the short distance from bowl to mouth. The solution? A small cup--they now drink their soup and love it!
Similarly, when we eat salad, I rip up the leaves into very small pieces.
3. A spoonful of Ranch dressing (or ketchup) makes the medicine go down.
If I stir in a good-sized dollop of Ranch dressing into the small lettuce pieces, that salad sails down the throat. If we can dip our meatballs in ketchup, more meatballs are consumed. I view condiments such as these as necessary evils. Sure we want them to learn to eat meat without dousing it in ketchup, but for the time being, don't sweat it. They are learning in the process that they like salad or meat or cucumbers or whatever. Someday, they'll no doubt be brave enough to try a different condiment on that familiar salad.
4. Get the old standby's at restaurants.
We eat a variety of healthy food at home. When we go out, then it's a treat to get chicken fingers and fries. My kids will eat well at the restaurant instead of complaining and throwing food, we won't waste money getting them something they don't like and won't eat, and I don't have to worry that they're not getting enough nutrition. One meal of fries once in a while isn't going to kill them.
5. Don't make food a big deal.
We don't make our kids clean their plates (gasp!). They aren't allowed seconds of anything until they've at least tried everything on their plates. Toddlers and preschoolers have random appetites; sometimes, they're just not hungry, so don't force the issue. We do not offer lots of snacks between meals, so that ups the chances they are actually hungry for the meal. In contrast, when they suddenly develop voracious appetites, I'll help the meal out with graham crackers or cheese sticks or whatever. When they hit a growth spurt, sometimes they really just need some extra calories; it's not life or death if those calories are coming from crackers instead of carrots especially if the general day/week is somewhat balanced.