I suggest to choose which day a week you want to introduce new foods or recipes to your family. Stick with it. You will have days where the food item doesn't go over well. Other times you will.
Each new food or recipe must be tried with one full bite. No licks or half bites. A full bite in order to get the flavor the food or recipe is intended to give.
Try combining old flavors that you know the family loves with new ones. I love spinach. I have learned I can add it to recipes. As long as I don't use alot of it. As spinach can be overpowering. Thus, canceling other flavors out. Same thing with onions, bell peppers, and garlic.
If you are looking for ideas of new foods and recipes to try out. Check out magazines, food shows on tv, Pinterest, and food blogs. You will be amazed at all the different variations of food combinations you have never tried.