1. To create the illusion of rooms in a large, open area, use bookcase room dividers. Fill shelves with personal items and photos to imply a bedroom, fancy kitchen tools and cookbooks to separate a kitchen. For a library ... you get the idea.
3. When decorating your bookcase room divider, alternate rectangular objects with round or angled art. A long row of books can look ponderous. Break it up with a statuette or favorite photo. Look at sample images on this site for ideas.