Well... first I have to say that if this is your first year in business and you're not familiar with the tax deductions/credits available to you, I would strongly encourage you to hire a CPA or qualified tax preparer to help you with your taxes.
Second: read, read, read! Even if you hire a tax preparer you should have a basic understanding of income taxes for small businesses/self employed persons.
Third, keep excellent records. Whether you prepare your own return or hire it out, good records are a huge time and money saver.
Home business tax tips is a big topic, so it's kind of hard to answer your question in one post. However, I can list the more common deductions for home businesses. If you have a more specific question, you might post it here as well.
Common tax deductions for home businesses:
Inventory
Automobile expenses - standard mileage deduction or actual expenses
Advertising/marketing
Supplies
Office Supplies
Depreciation on furniture or equipment
Insurance
Accounting and legal fees
Home office deduction
Phone, internet, website
This is just a basic list. There are many more deductions that you may be eligible for. You might want to review the IRS Publication 535 - Business Expenses at
www.irs.gov