The most common itemized deductions are medical expenses (reduced by 10% of your AGI), state income tax, real estate tax, home mortgage interest, and donations to charity. (You can deduct sales tax instead of state income tax, but living in New York the state income tax is likely to be more than the sales tax.)
The starting point in computing your New York Itemized Deduction amount is your federal itemized deductions from Federal Schedule A. However, differences between federal and New York State tax laws make it necessary to make certain adjustments to your federal itemized deductions in computing your New York itemized deduction.
For example, the New York amount is reduced by the state taxes deducted on the Federal Schedule A.