Take everything off your shelves, and sort them into groups. Group large, medium and small books together. Separate dark books from light books. If you have a large number of any one color of books, place them in a separate pile. Sort other items, such as small and large decorative pieces, into groups. Remove anything that is not attractive, and discard it or store it elsewhere.
Start with the color of books you have the most. This may be books in dark colors, light colors or a single color such as gray. Select five or six medium-sized books in this color, and place them upright on the left side of the top shelf. Place another group of these medium-sized books in the middle of the middle shelf. Lastly, place a group of large books in this color on the right side of the bottom shelf. You have created a diagonal line across the shelves.
Select another color of books, and distribute them evenly in the large spaces remaining on the shelves, placing the largest books on the lower shelves. Repeat this process until you have filled two-thirds of the bookcase space.
Fill in the remaining spaces with decorative items and stacks of three or four small books placed horizontally. These stacks can be used to hold the vertical books upright
Place small decorative items on top of some of the stacks of small books. Leave about 10 percent of the total area of shelves empty so the bookcase doesn't look overly cluttered. Store any remaining items elsewhere.