Your best bet is to get a good CPA to work with that can help you through this. There are a LOT of tax advantages in having a small business run from your home, not just the deduction of a percentage of your house. I've operated a successful business from my home for about 8 years and never claimed a percentage of my house, because my CPA advised against it. I have gotten many other advantages though.
Someone mentioned that you had to show a profit, and I don't believe there is any such rule. You DO have to operate it as a business though, and in a manner that you could achieve a profit eventually. That means things like forming a business structure... either sole proprietorship or LLC/S-corp. You would also want to have a business bank account and business credit card and keep your business and personal expenses from being mixed up. If you are selling, you need to deal with sales tax if its required on what you are selling. You may need to deal with insurance. You would want to have some actually business website, phone number, business cards, etc. So if you are really running a small business, regardless if you are making a profit or not, then it can be advantageous tax wise... but if you are thinking you will just designate a room in your house as a studio and then you can deduct it when you've not set yourself up as an official business, then you will likely get into a bit of trouble with the tax agencies.