The OCI workflow

For those who are US Green Card holders and are waiting on getting your citizenship before returning to India, here is a sequence of things I did to make it happen.

Before you start anything, make sure you have a PAN card in India and/or Aadhar Card. It will smoothen your plans

1. 90 days before your 5th Green Card anniversary, you may apply for your US Citizenship (form N-400 downloadable at http://www.uscis.gov/us-citizenship/citizenship-through-naturalization ) The form is simple as long you haven't done anything complicated and are leading a vanilla and decent life.You will need to fill one for everyone who is above 18 years of age. For those under 18 who are Green Card holders, you don't need to do anything now.
2. About a month after your receive your receipt, you will receive an appointment for your Bio-metrics. That same day you will receive a booklet &/or CD for the upcoming test.
3. And possibly a month after that you will be called in for an interview... It is really simple.. If you can read this article and follow CNN, it will be a piece of cake. The Immigration officers just want to know that you can read and write English and communicate well.
4. Now comes the big nail biter.. waiting for Swearing In ceremony. It will normally be a date after your official 5th year Green Card anniversary. It is on that day, you will be asked to bring in your Green Card for it to be clipped and be officially sworn in as  US citizen. (Don't worry if you forget your Green Card that day... I am told Immigration have a other paperwork to fill if you lose you Green Card) You will be awarded a Certificate of naturalization with your name, picture and signature. All the above steps are better explained at http://www.uscis.gov/sites/default/files/USCIS/files/M-1051.pdf 
5. With this new found sense of American Pride, the next thing you must do is apply for a US passport. Do not go for any of the passport offices in your city, you may get a non-practical appointment with a 3 month waiting period. Visit a Country Clerks office in a nearby town/county which accepts walk-in. Be sure to have all your paperwork before hand and extra pictures. Call ahead and find out if they will accept personal checks or bankers checks or money orders ?
6. Now you are no longer a citizen of your country but do have a valid US passport... What do you do ? Well India permits you to travel up to 3 months on your Indian passport (I am not sure if it is only to India). This is why I recommend you apply for a US passport on the day of becoming a US Citizen.
7. You should receive your new passport within 10 - 14 days max, even though you are told that it would take a month. 
8. Next, take a photocopy of the relevant pages from that passport and assemble your OCI package and application for Surrendering Indian Citizenship, along with money orders & exact photos. Apply for it thru Travisa . Remember to open a free Fedex A/C so that all you have  to do is send a self-addressed Fedex Domestic label and envelope along with your pkg.
9. Remember NOT TO SEND  your US passport at this time. Travisa will intimate you when to do so. The application from Travisa is send to the Indian Embassy or Consulate and is shipped to New Delhi for verification and allocation. This is then returned back to the respective Indian mission and they in turn notify Travisa. Travisa notifies you that you would need to send in  your US passport. They will get it stamped with the OCI and ship your Old Clipped Indian passport, OCI booklet, US Passport and also the same sheet that you filled in for surrendering your Indian citizenship with simple stamp on it.
10. For some who live in the city of the Indian Embassy or Consulate, you may walk-in to the Travisa office and submit your paperwork. The process after submission remains about the same period, but the process of submission of Passport and the final leg is quicker and more real-time. So if you live in DC, NYC, Chicago, Houston, Atlanta and anywhere there is an Indian mission, you may just walk up to Travisa and get your paper work done face to face, and not rely on the logistics industry.

I heard some folks who acquired their US passports and obtained an Indian Visitors visa and flew to New Delhi and stood in queue in at the Home office and got the OCI the same day. I am not sure about this.

I hope this helps you.