Here are some suggestions that may help you overcome your food aversions and try new things:
Make a minimal effort, to begin with: Eat a small amount of food you've never tried before or used to hate. The possibility exists that you will come to enjoy it, or at the very least find that you can tolerate it in moderation.
Experiment with different cooking techniques; the final product will have a different flavor and texture depending on the method used. Do you like boiled food? If not, try grilling it instead.
Alternatively, you could try combining new food with old favorites. If you don't like vegetables, for instance, you could try eating them blended with a sauce or dressing that you do like.
Be receptive; don't form strong opinions about new foods before giving them a fair shot. It's important to keep in mind that your preferences can shift as you get older.
Don't make drastic changes to how you eat overnight; take it slow. Add new foods to your diet gradually to give your body time to adjust.
Developing a more adventurous palate and trying new foods is a process that can pay off in the end.