It's way easier than, let's say, quitting smoking. Start with liquids like orange juice . Buy an economy-sized box of orange juice or apple juice. Then before heading off to school, grab a box of juice and drink it on your way out. Orange juice and apple juice are great breakfast starters.
Milk is the ultimate breakfast drink.
However, it can taste quite bland without cereal or bread complementing it. If your family is a coffee family, it's also a good idea to drink some coffee. The carbohydrate family contains a myriad of breakfast foods. Cereals and breads are the most common ones. When choosing cereal, don't go for the sugar-loaded boxes such as Coco Puffs.