First of all, don't paint everything black. Especially the walls. Few things will freak out parents more than to find that little Janey's room absorbs more light than a stealth bomber. Leave the walls white, or if they're a kiddie pastel, ask to paint them a nice, plain white or some other neutral color -- parents will probably love that because it sounds so reasonable and mature. Don't paint furniture either, unless your parents agree to exactly the colors and finishes you plan to use. It's not worth the hassle of arguing about things that your parents have every right to control (they paid for the house and the furniture, didn't they?).

Instead, concentrate on your bed and the furniture surfaces. These are non-permanent areas that are probably what you see most anyway. You can also hang posters and prints on the walls, but do get an okay if you're nailing into the walls (and if you make a hole, patch it up).

Decorate your bed with sheets you purchase either from a discount store or thrift shop. Sew trims on plain sheets to dress them up. Make a comforter cover out of two sheets or fabric you like. Sew new pillowcases or make small throw pillows. Make your bed look more like a sofa. Hang fabric over your bed like a canopy and weave tiny Christmas tree lights under it.

On your dresser and desk, place objects that appeal to you and fit your own gothic sensibilities. You can drape fabric over the dresser or desk surfaces and then arrange your treasures there. Vases of dried roses, candles, gargoyles, framed photos, postcards, Sanrio toys, whatever you like. Display treasures from your wardrobe or any collections you have.

Instead of spending a lot of time arguing about things your parents will hate, invest that same time making small embellishments to your room. Surround youself with little things you love and don't sweat the big stuff till you're on your own. Then you can really go wild...