If you make under $42,000/yr, call the Volunteer Income Tax Assistance Program at 1-800-829-1040 to find an assistance site where they'll help you prepare your return.
If you're over 60: Enter your location into the AARP Tax-Aide Site Locator for help with your return. If you're under 60, call to see if they'll help you. They might.
The locations of VITA and AARP tax assistance sites are available online here. Volunteers will see if you're eligible for the Earned Income Tax Credit (EITC) or the New York City Child Care Tax Credit.
A list of paperwork you should have available when you're ready to prepare your taxes is here.