See 132 Expand the Capacity of a Small Room.
Concentrate on making your apartment both attractive and functional. Keep those two concepts in mind in all that you do; you’re more likely to keep your place clean and organized if you like the way it looks and works.
Consider how you’ll use your apartment. Is it just a crash pad for yourself, or will you entertain guests? Do you work at home? Do you have sports equipment or hobby supplies? Define your floor plan and storage options accordingly.
Separate your sleeping area in a studio with freestanding screens or bookcases. Paint the back of the bookcase with chalkboard paint and use it for messages and brainstorming, or cover it with fabric and use it as the headboard for your bed.
Buy a bed that’s designed for small spaces: a loft bed, Murphy bed, sleeper sofa, daybed or futon. These let you reclaim the sleeping area when you’re awake. Also look at beds that have storage drawers under the mattress instead of a box spring.
Get a drop-leaf table. Fold out one leaf and use it as a desk, fold out both leaves for dinner parties, or fold up the whole thing and push it against a wall when not in use.
Look for home office furniture that can fold up and roll out of the way when not in use. If you already have a favorite worktable or desk, put it on easy-rolling casters.
Group most of your belongings in one or two areas. More floor space will make your place seem larger.
Go ahead–use large furniture in a small space. It can actually make a small space seem larger. Many pieces of small furniture tend to look cluttered.
Think vertical. Get 7-foot-tall (2.1 m tall) bookcases instead of the standard 6-foot-tall (1.8 m tall) units, and put baskets of small items and papers on the top.