Should I renew my passport before going for visa stamping?
Yes, renew your passport BEFORE getting the visa/visa stamp! Ideally, your passport should be valid for the entire I-797 validity period. Each U.S. consulates website contains a discussion of the interview scheduling procedure and a list of documents that should be presented during the visa interview. The documentation required can vary depending on the consulate, so have a look at specifically what is required in your situation. The list of exactly what you are required to do BEFORE (payment) and DURING (bring to) the visa interview are to be found on the website of the US consulate where you are. They are not all the same. Get it all done right before you get here!