Just because it is fun (don't let yourself get overwhelmed) check out
Balloon HQ - Educating the World About Balloons and Balloon Art
Look at the very basics of the hats they make. Yes they are really fancy and use 10 or 15 balloons but look at the part that actually sits on the head. Usually the base of the hat is one or two balloons and the rest is accents, pretty stuff, but the hat would still look neat without it to the average person on the street. It just wouldn't work for a book if it wasn't so fancy.