Determine whether you earned income in more than one state during the year. Your W-2 forms will show the states to which your income and withholding are attributed.
Determine whether you lived in more than one state during the year. Each state has its own definition of residency, but intent to stay can be used by most.
Determine whether you lived in one state and worked in another.
Verify that you are the legal owner of property in a state other than your state of residency and had gross income (income before expenses) from the property. Some states, such as Florida, tax assets rather than income, so check out the rules for any state in which you own property.
Check out the filing requirements for all states in which you lived, worked or owned income-producing property.
Obtain the proper state forms as well as instructions by mail or over the Internet. Some states have combined part-year resident/nonresident forms, while others have separate part-year resident and nonresident forms.
Alternatively, you can take your tax documents to a tax preparer who has experience, as well as having the forms and instructions on hand.