1. Focus on the mantel only. Mantel-only fireplaces are one way to grab a sliver of space but maintain an uncluttered look -- a particularly important goal in small rooms. And mantels can be more hardworking than you think: Try adding small, color-coded stacks of books or decorative items so they don't clutter side tables.
2. Add open shelves. Open shelves are a simple fireplace built-in and a practical, adaptable way to gain lots of storage. In narrow fireplace nooks, they work well to fill up what would otherwise be dead space. If there are no windows to the side of your fireplace, consider taking the shelves from floor to ceiling. Otherwise, ending them at mantel height is a good way to meld the look of the built-ins with the fireplace.
3. Supply a little -- or a lot -- of space. Before you add a fireplace built-in, you have to evaluate the rest of your home. Do you need just a few key spots for books? Or does your home already feel overcrowded? That might help you decide how much storage to add, whether it's floor-to-ceiling units or a simple, low bookcase or bench.
4. Go recessed or flush. Many fireplace built-ins are stepped back by several inches to accommodate the depth of the fireplace while providing usable storage that isn't too unwieldy. Other built-ins are in the same plane as the fireplace. Stepping back the built-ins offers a bit of visual relief, particularly useful in a small room.
5. Decide on symmetrical or asymmetrical. Where your fireplace is sited will influence where your built-ins go and whether they are uniform on both sides. But there are no rules: Do what works with your house and your needs. Contemporary built-ins might work well just to one side, particularly if the design is sleek and unfussy. More traditional homes might feel best with symmetrical built-ins on both sides of the fireplace.
6. Boost the base. If your fireplace hearth has an elevated base at low-seating height, you might be able to extend that to both sides for low shelves or drawers that add storage (and more seating, too).
7. Mix and match base and shelves. An elevated base and open shelves work well together, particularly with fireplaces that are centered on a short wall. It's a look that's often seen in traditional or cottage-style homes and can give a space visual balance.
8. Close up the storage. Doors -- those with glass, metal, or solid fronts -- are another fireplace built-in option and a way to add visual variety. Solid doors contain and conceal clutter, while more transparent doors provide display space.
9. Pick materials and design details. Whatever fireplace built-in setup you decide on, use your home and your fireplace for cues on materials and details. Built-ins are a good way to repeat certain design elements -- for example, a material or molding type found elsewhere in the room.
Always keep safety at the top of your mind when designing and installing fireplace built-ins. Your local building codes and ordinances might specify materials and required dimensions to maintain noncombustibility.