One thing which worked back when my son was younger and pickier was the simple--pick whatever salad dressing or condiment your kids like and serve it with the veggies to dip in. My son loves Italian dressing, has since forever, and through the whole dipping thing I've gotten him to love tomatoes, broccoli, carrots, celery, cukes, sauteed zucchini/squash. Another one, if they like marinara sauce or tomato-basil sauce, get them to try eggplant parm.
I have been lucky--my kiddo loves his veggies, but it wasn't always so. He's always loved tomatoes, and loves dipping, so that's how I got him into the rest. Another suggestion is a no-thank-you bite. I don't know how old your kids are, but it takes a child up to age 12 up to 10 tries of a new food to know if they actually dislike it or not. When my son was younger I made him try EVERYTHING I made, except really spicy food. He had to try it EVERY time I made it, even if he hated it the time before. By try I mean a bite or 2, not the 'finish it or you're grounded'. There are very few things he won't at least try now, and he really enjoys trying new things and suggesting making new things at the age of 12. He doesn't like everything he tries, but it's fun