In Connecticut, if you make less than the income threshold you may not be obligated to file a state return. You should check the current year filing requirements before you begin the process of preparing your form. Even if you are not required to file, it may be to your benefit to do so, especially if you are entitled to receive a refund.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040booklet.pdf 

The state of Connecticut taxes all forms of earned income, such as wages and self-employment earnings. Some unearned income sources are also taxable, these include unemployment compensation, lottery winnings and rental property income. See the tax form instructions for a full list of taxable income sources.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040booklet.pdf

To get started filing your Connecticut state tax return, your first step is to assemble all of the documents you need to prepare your tax form. This will include the following:

1. Your Social Security number
2. Your current mailing address
3. The full name and Social Security number of your spouse, if you will be filing a joint tax return
4. Your earned income for the year - If you are employed, use the total taxable wages as reported on your Form W-2 or Form 1099. If you work for yourself, add up your gross earnings and then subtract your qualified business expenses.
5. Your unearned income received that is also subject to state tax - Examples of this include capital gains, bank interest, pension payments, etc.
6. The state income taxes you have already paid during the year - Employees will see this on Form W-2 as state taxes withheld. Self-employed taxpayers can use the total of any estimated state tax payments they have made.
7. A copy of your completed federal income tax return, if you will be filing onehttp://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040booklet.pdf 
   

Your Connecticut state tax return will begin by using the amount of your federal adjusted gross income, or AGI, so you should complete your federal tax return before you begin this process. If you won't be filing a federal return, you may want to talk with a tax preparer who can help you to calculate your AGI.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040booklet.pdf 

To begin preparing your state tax form, obtain a copy of the return for filing. If possible, consider using electronic filing as a method for preparing and submitting your return. E-filing is a safe, accurate and convenient way to file your tax forms. Since it also reduces processing time, e-filing will enable you to receive any refund due up to 6 weeks sooner than filing by mail.http://www.ct.gov/drs/cwp/view.asp?a=1433&q=265866 

There are several e-file providers listed on the Connecticut Department of Revenue website. Some programs even allow taxpayers who meet certain criteria to e-file their federal and state tax returns for free. If you use tax software to prepare your federal tax return, you will usually be given the option to include your state return for an additional fee. To use any of these electronic programs, simply follow the prompts using the information detailed in step 1.http://www.ct.gov/drs/cwp/view.asp?a=1433&q=265866

To file your return by mail, you need a paper copy of the state tax form. If you have access to the Internet, you can download Form CT-1040 "Connecticut Individual Income Tax Return" and the tax instruction booklet from the department of revenue website. If you do not have Internet access, you can generally find hard copies of these at your public library during tax season.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040.pdf 

If you are completing the form by hand, be sure to write clearly and use black ink. This will help you to avoid processing delays. Begin the form by writing in your full name and Social Security number. Then write in your spouse's name and Social Security number and complete the address section.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040.pdf 

After you begin the tax form, read the tax instruction booklet carefully to see if there are any income adjustments you need to make or state tax credits you can claim. Adjustments to income may be necessary to account for income that is taxed by the state of Connecticut but not the federal government or vice versa. Eligible tax credits will directly reduce the amount of your state tax liability.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040booklet.pdf

Carry your federal adjusted gross income from IRS Form 1040 to line 1 of the Connecticut return. Then turn to Schedule 1 "Modifications to Federal Adjusted Gross Income" to list your income additions and subtractions. Enter the total of these on lines 2 through 4 on page 1 of the Connecticut return and then figure your state adjusted gross income on line 5. Consult the tax table located in the instruction booklet to assess the amount of state tax owed on your income. Enter this amount on line 6 as your tax.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040booklet.pdf 

Subtract any qualified tax credits you can claim on Schedule 2 to calculate your total tax owed on line 14. Separate your earned income by source on line 17 then deduct your state taxes already paid through withholding or estimated tax payments. The result will be either an overpayment (refund) or an underpayment (balance due).http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040.pdf 

Sign and date the form and have your spouse do the same, if necessary. Make a copy for your records. If you have a balance due, write out a check or money order for your outstanding taxes owed. Send the completed form, along with any payment, to the appropriate address listed on the return. Be sure to submit both by April 18, 2011.http://www.ct.gov/drs/lib/drs/forms/2010forms/incometax/ct-1040.pdf

If you'll be unable to complete your state return before the filing deadline, you may want to learn about how to get a state tax extension in Connecticut.