Make filing US taxes easier by gather all of your records together. Take the time to get everything in order before you start doing anything. It will take a few minutes, but it will pay off later.
Get your records, tax forms, instruction, your calculator, and the IRS Pub 17 together. The IRS Pub 17 form can be downloaded from: http://www.irs.gov/pub/irs-pdf/p17.pdf. Read all of the forms thoroughly so you have a good idea of the information you will need before you do anything else. This includes the 1040EZ, 1040A, or 1040 return, and the supplemental forms (Schedule A, EIC form 596, Child Tax Credit form 972, Dependent Child Care Expenses form 2441, Additional Child Tax Credit form 8812).
The W-4 is not the same as a return. The filing status and allowances are between you and your employer. On the W-4 the filing status is nothing more than telling your employer what to withhold from your check. It's not the same as the filing status on your return. You can adjust this this to affect your refund at the end of the year. You have the option of choosing from more than one status.