I have finished a 12x15 heritage album and have a set of three I am working on right now.
NoirCat has given you some good ideas.
I would add: Only put in memorabilia and pictures you have inherited from family. I have genealogy records separate from things I have received from family members. You can still says who is who with pictures. Otherwise, the heritage albums will never get done.
Think of your heritage albums as being a place for family artifacts.