Look at pictures of bald eagles in magazines, books and on the Internet. If possible, visit a local zoo or, if you're lucky enough to live in bald eagle habitat, view them firsthand. Nothing compares to watching their behavior in the wild. Watching them soar, listening to their distinctive call or watching them dive for fish will teach you a great deal about their size and social behavior.
Read books, scientific journals, or articles about the bald eagle. This will give you useful background information about the eagle's habitat, what it eats, and what it looks like. It will also provide you with the history of this formerly endangered bird and what once threatened its existence.
Watch videos on the bald eagle to learn from scientists and others who have lived and worked with and researched bald eagles. There are many different kinds of videos available, from educational to ones designed to entertain. Depending on your interest, you may want to watch several types to gain a different perspective on the bald eagle.
Study the representation of bald eagles in art and literature over the years. This will give you a sense of how the bald eagle has been depicted at different times in different cultures. Also, read first-hand accounts of individuals who have lived with eagles.