Method 1 - Entirely on your own
Method 2 - Using a free service
IMP- I do not bear any responsibility for the accuracy of the below given information. Please act on your own responsibility.
1) Proof Documents: Have all the necessary documents (Like Form 16, TDS Certificates, Interest certificates, Pension certificates, etc) in hand.
2) PAN: Know your PAN number (Besides the PAN card this information can be found in your proof documents and also from this link - Know Your PAN).
1) In order to choose the correct ITR and to download its respective ITR-Preparation software go to this link: https://incometaxindiaefiling.gov.in/portal/downloads.do (This is an Excel tool so you would need MS Office or similar software to use this tool). Relevant instruction about the form can also be downloaded here.
a) Designation of assessing officer: You can get this from this link – Know Your Jurisdiction. Eg. ITO, WARD 1(1) In this opinion with the advent of efiling and with the centralized submission of ITR-V(we will discuss this later) this field is largely un-important. So don’t fret about it much.
b) Tax payable on Aggregate income (8a): In case your only source of income is your salary/pension then this info can be got from the Form 16 itself. However if you have some pension or interest income details that has not been mentioned in your form 16 but you have included in the ITR form entries 2a and 2b then go to this link and calculate your applicable tax: Tax Calculator
c) Resident Status: Many would assume that just because they are currently in India while filing their returns then they would qualify as residents. This however is not entirely true. If you are an Indian citizen who stayed 182 days or more during the particular financial year then you are a resident. For others please check this link -- Resident Status.
4) After completion of form. ‘Validate’ (available macro button) the form and then click ‘Generate’. This will generate and xml file.
5) Go to Efiling website and upload this xml file.
These providers offer a variety of free tax filing services: