4. Use reclaimed materials. Most metropolitan areas now have several architectural salvage shops. While materials made from recycled materials are great, remember that it's reduce, reuse and then recycle.
Reclaimed materials are a great way to reuse. Go to your local salvage yard and think creatively. Here a wall is dressed up with old boards, some with the original paint on them. Reclaimed doors, light fixtures and tile are all great ways to give a space character. Don't be afraid to use something for a purpose other than what it was intended for; my coffee table at home is made of an old exterior shutter.