Measure the height of the bookcase and find a location in your room that will accommodate the height of the bookcase as the width. For example, if the bookcase is 6 feet tall, you need 6 feet of horizontal space along a wall to turn the bookcase sideways.
Place the bookcase on its side and remove any removable shelves from the bookcase to secure them vertically. Discard the pegs or clips that hold the shelf in place horizontally. Run a bead of wood glue along both side edges and the inside long edge and fit the shelf into the bookcase at the proper spot. Clamp the shelf in place with a band clamp that encircles the entire shelf and bookcase to ensure that the shelf does not move while the wood glue sets up. Consult the wood glue label for drying time and remove the band clamp after the drying time elapses. Repeat the same process for each removable shelf. If your bookcase does not have removable shelves, proceed without gluing.
Situate the bookcase snugly and securely against the wall so the back of the bookcase sits flush against the wall from the top edge to the bottom edge where the wall meets the floor.
Plan how you will use the bookcase. Depending on the number of shelves, you will now have vertical spaces between vertical boards where you did have horizontal spaces and shelves. Use some of the vertical spaces to hold stacking baskets or tall room decor such as candlesticks or vases.
Find the center point on the underside of the top shelf of the bookcase between two vertical boards by measuring and make a small “X” at this point. Drill a pilot hole with the drill and screw a small hook into the hole. Use the hook for storage -- hanging purses, backpacks, bags or even lightweight coats. Repeat this process to transform as many vertical spaces into hanging space as you desire.
Place items on top of the top shelf of the bookcase for horizontal storage. Baskets, books, bins and home decor items such as pottery and candles may look perfect along the top shelf of the sideways bookcase.