Group books of similar size and place them on the shelves, starting from the smallest books on the top shelf and moving down in size until the larger books are on the bottom shelf. Placing heavier books on the bottom shelf will create a uniform look and properly distribute weight to the bottom of the unit.
Separate hardback books from paperbacks. Create a section of the bookshelf for only paperback books, and arrange them on the shelf in an ascending fashion so the taller books are centered in the middle of the shelf. Keep books of relative size together rather than alternating small and tall books.
Leave about 10 percent of each shelf open to keep the bookcase from looking too crowded. Apartment Therapy suggests leaving space on each shelf to create a roomy look, and the extra room will prevent damage to the spines and covers of the books.
Group books by color to add an artistic element to the room. Between each color section, place a knickknack or vase to break up the color palette.