1. ATM Fees, Credit-Card Fees, and Interest
You can deduct ATM fees, credit-card fees, and other bank charges incurred on your business accounts.
Category this deduction falls into: Office expenses; interest

2. Books, Magazines, and Newspapers
Business-related books and subscriptions to magazines, newspapers, and trade publications are deductible.
Category this deduction falls into: Office expenses

3. Business Cards
Deduct the cost of business cards for yourself and your employees.
Category this deduction falls into: Office expenses

4. Cell Phones
If more than half of your cell-phone use is for business, deduct that proportion of the cost, up to the full amount if you have a dedicated cell phone for your company. But if you use your cell phone for business less than half the time, you can’t deduct it.
Category this deduction falls into: Office expenses

5. Child Care
If you offer employees child care, you can deduct the cost. You can offer employees up to $5,000 a year in dependent-care benefits that are excluded from their wages, tax-free to them and deductible for you. Employees may qualify for other dependent-care tax credits. For more, check the IRS guidelines.
Category this deduction falls into: Employee benefit programs

6. Cleaning Service
The cost of a cleaner or janitor to maintain your place of work is deductible.
Category this deduction falls into: Office expense

7. Coffee and Snacks
Write off what you pay to keep yourself and your staff caffeinated. Other small office snacks are deductible, but meals for yourself are not, and the cost of meals provided to employees can only be deducted if there’s a business reason for having them eat at work.
Category this deduction falls into: Office expenses

8. Company Parties
Deduct the entire cost of a party where all employees are invited. Other business parties or events that are thrown to promote the business are considered entertainment, and are therefore 50% deductible.
Category this deduction falls into: Office expense, entertainment.

9. Disabled Access
Small businesses can get credits and deductions for the cost of making their place of business accessible to people with disabilities. For more information, see the IRS guide.

10. Domestic Production
Even nonmanufacturers may qualify for a break called the Domestic Production Activities Deduction. Firms including architects, engineers, software makers, and film producers all may be eligible for this deduction, which is equal to 6% of net income from domestic production activities. It maxes out at 50% of W-2 wages, however, so non-employer firms don’t qualify. For more, see the IRS instructions.

11. Dues
Deduct membership fees in trade organizations, professional groups, and chambers of commerce. Portions of dues that are for political lobbying are not deductible, and dues for political clubs or recreational groups aren’t business expenses and can’t be deducted.
Category this deduction falls into: Other expenses

12. Garbage Pickup
If you pay to have your trash hauled, you can deduct the cost. Some manufacturers may have to add this to the cost of inventory.
Category this deduction falls into: Utilities

13. Greeting Cards
Greeting cards to clients and prospects count as tax-deductible expenses.
Category this deduction falls into: Office expenses

14. Internet Access
You can deduct the cost of your Internet access, but if you use the connection for both business and personal purposes, you can only deduct the amount used for business.
Category this deduction falls into: Office expenses

15. Lists
If you buy or rent lists of e-mail addresses, mailing addresses, or phone numbers, you can write off the cost.
Category this deduction falls into: Advertising

16. Parking and Tolls
Business-related parking costs beyond what you pay to park at your regular place of work are deductible, as are tolls paid during business travel. Parking violations and other tickets are not.
Category this deduction falls into: Car and truck expenses

17. Postage and Mailing
Stamps, other mailing costs, and the cost of renting post-office boxes are deductible.
Category this deduction falls into: Office expenses

18. Research and Development
You can deduct the cost of developing new products or improving existing ones. For more on this, see this IRS article on R&D deductions.
Category this deduction falls into: Other expenses

19. Retirement Plans
Contributions to tax-deferred retirement plans such as IRAs or Self-Employed Pensions can reduce your tax bill, because that income won’t be taxed until you withdraw it from the account. You can count contributions to these plans made through Apr. 15, 2009 for the 2008 tax year. You can also deduct contributions made to employee retirement plans. For more information, see the IRS instructions (pdf).

20. Seminars, Classes, and Training
Education that improves your knowledge and skills in your current business is deductible, but training for an unrelated trade is not. Employers can fully deduct the cost of job-related education for their workers. Employers who pay for nonjob-related education for workers can write off up to $5,250 as part of a formal educational assistance program.
Category this deduction falls into: Other expenses, employee benefit programs

21. Shipping
If you pay for customers’ shipping and handling on the goods you sell, you can deduct those costs.
Category this deduction falls into: Other expenses.

22. Software
The cost of software can be depreciated over three years or deducted immediately under the Section 179 expensing, which lets you write off up to $250,000 in capital expendiutures.
Category this deduction falls into: Office expenses or depreciation.

23. Tax Preparation
You can deduct what you pay a tax preparer for the business portion of your taxes.
Category this deduction falls into: Legal and professional services

24. Trade Shows
Write off the entrance fees for trade shows, conferences, and other industry meetings. Travel costs and meal expenses may be deductible under the rules for business travel.
Category this deduction falls into: Other expenses.

25. Web site
Deduct your hosting fees and the cost of your domain name. You can generally deduct the cost of designing and setting up your Web site as well, although expensive Web sites may have to be depreciated over three years.
Category this deduction falls into: Advertising

Courtesy of BusinessWeek Small Biz Insider