Talk to a tax professional. The IRS really doesn't like the deduction, and it's a concept (like independent contractors) that is often not done properly.
You need to, at a minimum, have records, including timestamped photographs, proving that:
- The part of your home used for business is exclusively for your business. If your wife works out of the room, you can't deduct.
- You need to use the space regularly for business.
- It needs to be a principal place of business. "Principal" has a specific meaning.
Remember, documentation is key, and must be filed and accessible for a number of years. Poor record keeping will cost you dearly, and the cost of keeping those records is something that you need to weigh against the benefit.