If you are in US and your passport is expiring, you can renew it from the Indian Consulate in SFO. This is available only to people who are in US on a non-visiting visa. If you are on a visitor's visa, you need to renew your passport in India.
You can renew your passport by mail or by appearing personally at the consulate. I have listed the required documentation below. If you are going personally, take all the original documents along with the photocopies. When applying by mail, all the photocopies need to be notarized if you are not sending the originals. The documents that you need are :
1. Original passport and a photo-copy.
2. Document that proves your status in US (Greencard / EAD / I-797)
3. Address proof. (PG&E Bill / Apartment lease / Driving License with current address)
4. Photos. Two 2" X 2" photos. ($4.99 at Costco / $7.99 at Walgreens / Free at epassportphoto.com)
5. $40 fee. No personal checks / credit cads. Take a money order / cashier's check or pay with your debit card with an additional $3 fee.
6. Self-addressed USPS express mail cover to receive the documents back (optionally, you can pick-up)
If you are newly married and want to add your spouse's name on your new passport, you need the following documentation.
1. Original passport of spouse and photo-copy.
2. Marriage certificate
3. Marriage photos and invitation card
4. Affidavit. Signed and notarized by both.
Fill the online application and get an appointment. Print out the 4 pages that come out after finishing the online form and fill the rest of the details with pen. Paste one photo on the first page and pin the other on the last page. If you are applying by mail, ignore the appointment date and send the documents by mail right away. If you are applying in person, visit the consulate on the day of the appointment.
Everyone gets the time of the appointment as 9am. Consulate is open from 9 to 12 only. So, be there by 9am and take a number to be called. Parking near the consulate is very less and you have to drive around to find a vacant space. So, give yourself additional time to find a parking space.
If you are applying in person, you will be given a choice to pick-up your new passport from the same place or get it by mail. To pick-up your passport, visit the consulate between 4 and 4:45 pm on the date given. To get it by mail, use self-addressed cover specified above.
For all additional questions and information, visit their website.