Itemizing requirements
In order to claim itemized deductions, you must file your income taxes using Form 1040 and list your itemized deductions on Schedule A. You cannot file your taxes using Forms 1040A or 1040EZ if you want to itemize your deductions; only the standard deduction can be taken on these shorter forms.
Once you have entered your expenses on the appropriate lines of Schedule A, add them up and copy the total to the second page of your Form 1040. This amount is then subtracted from your income to arrive at the final taxable income number.