In a previous article, you can find great info on how to deduct that space.
You must also consider that the home office is also the same as the home studio for most practical purposes of tax deduction.
See this article Home Office Tax Deductions
That normally are not available to most people.
Stage clothes and makeup.
You can't use the clothes for everyday use, but that's OK.
It's a deduction, and so is the cleaning of it.
Sheet music and recorded music to be as a teaching or learning source.
Music lessons for yourself are deductible.
Billboard magazine and other trade magazines.
Deduct "How to" books and manuals.
Rent for storage and rehearsal space.
Memberships in professional associations and unions.
Deduct copyright and trademark registration fees.
The expense of maintaining your website and e-mail for your profession.
Deduct promo demo's and printed material such as bio's and promo photos.
Up to $25.00 is deductible for gifts to industry professionals.
Repairs and upkeep of instruments.
Insurance on instruments.
Legal expenses for drawing up contracts of employment.
Did you get robbed/ripped off of your gear? Theft...
You can deduct some in full. Some have to be depreciated.
Get more info on that by checking the IRS Publication 946 ("How To Depreciate Property").
Some folks think they can write off the cable TV expense because they need to keep up on what is going on on MTV etc. or concert tickets, but I suggest that you ask your tax preparer.
This is only a guide, and before you file you should get it all reviewed with a tax professional. There are a lot of details, and we haven't discusses long term investment, health Insurance and other deductions that are used by all of us. This is designed to be a helpful guide for entertainers, performers and musicians.