To file an income tax return, first, collect all the documentation you need including bank statements, Form 26AS, investment proofs, rental agreements, and pay slips. Next, calculate the total income and choose among ITR forms based on your sources of income. You may also want to check if the Annual Information Statement is there as well or complete. You are to select tax system and claim deductions. Do not forget to fill your ITR form and once it is filled, submit the ITR form, check your return and respond to the Income Tax Department's messages as soon as possible as with any department, the quicker you respond, the better your experience will be.