Gluten is in some things that you wouldn't expect it to be in. Some of those things I learned the hard way.
Cereals
Some corn or rice cereals are actually NOT gluten free. Like rice Krispies and corn flakes. Both cereals include malt flavoring and the malt flavoring is NOT gluten free.
Dressings/ sauces
Some salads are not gluten free because the salad has croutons but if you go out to a restaurant you can probably ask with no croutons. Also on a salad the dressing can have wheat in it so make sure you read your labels. In sauces flour if often used as a thickener so be careful when eating soy sauce. Gravy can also use wheat as a thickener.
Soup
Soups can also have hidden gluten because wheat can be used as a thickener.
French Fries
French fries can be cooked in a fryer that also fries things with wheat on it. Make sure to be careful when you order fried foods.