We have a small room and I always de-clutter to make more space because we are getting more stuff each day especially when we have our son who has so much toys plus books. Anyway, I found this article over at Freshome.com.
How to maximize space in a Small Apartment:

Make your space multifunctional: Whether you live in a one bedroom, studio, or if you just have a lot of roommates, your apartment should be able to utilize one space for several functions. Your dining room table could serve as an office for your laptop when not eating, dining table at meal time, and possibly a work surface when doing hobbies and crafts. Utilize kitchen bar area for sitting, entertaining, dining, and extra work surface space when cooking. In your living room, use futons, and sleeper sofa beds for a couch in the day, and a sleeping area at night.
Utilize vertical and hidden storage: In a small space vertical and hidden storage is your best friend. For storing collectibles, books, and displaying decor, utilize tall display storage, shelving over doorways, and open shelving throughout your apartment. Hidden storage under beds, hanging organization accessories on the back of doors, and installing vertical storage in cabinets, can drastically maximize your storage capacity. In clothing closets, hang shelving in double tiers, and at varying heights to get the most of your closet storage.
Use light and color to your advantage: To make your apartment look larger, let ample light into your home as much as possible. Also use light colors, neutrals, and muted tones to maximize visual space. When your home looks larger, you will feel better and more at home in your small space. Try to avoid compartmentalizing your rooms with color. Use a unifying color throughout your home, like a neutral and define spaces with accent walls or with varying hues of the same color. This will make your apartment visually read as one large space.
Bring in eye catching furnishings: Even though your space is small doesn’t mean you can’t maximize on style! The great thing about having a small apartment is you don’t need a lot of furniture. For the few pieces that you do have, make them special and eye catching. A beautiful headboard in your bedroom, or even an entertainment center that commands attention from all your guests, can make your apartment interiors fun and enjoyable to be in. Don’t forget your walls too. Artwork, murals, and wall decals can make your walls come alive with color and life without much work. The more visually appealing your decor and furnishings, the easier it will be to remember how larger your space actually is.
I hope these tips helped a lot with small houses or apartments.