This post has a lot of photos but they take the project through the design stages of concept sketch, scale drawing, photoshop mockup, foam core mockup, client review and right on through to where the client cancels !! The description below the last photo describes the process. Double click the photos to enlarge.
Another great visualization tool is the foam core mockup. Essentially, we take scale elevations and floor plans, (all the same scale, obviously), paste them onto 1/4" foam core, cut them out and tape or hot glue them together to make a 'room'. If you're really into it, add furniture and people size cutouts. The model shown here is 1/2" to the foot making it about 7.5" wide, 5" high (10' walls) and 18" (36') long. In this case it was helpful for the clients but not so helpful for me, as, once they saw it, they realized it was going to be a space breaking piece of furniture that would rob their house of the open feeling they were looking for and they subsequently axed the whole project, moving the tv to another location in the room. I'm glad for them though as I think it would have changed the whole feel of the main living area of their house. Make a model, make a friend .....