Passport
A passport provides the identity issued by your country of citizenship and is a required document while traveling to the US, applying for US visas or immigration.

Validity
For nonimmigrant visa applicants, you are required to have passport valid for travel for at least six months beyond your date of intended stay into the U.S.

However, there are many countries exempt from this rule and are required to have the passport validity only for the duration of their stay in the U.S. Otherwise, the person will be admitted into the U.S. only until the date on which the passport expires.
Exempt countries list

For immigrant visa applicants, the passport must be valid for travel to the U.S. and must have at least eight months validity beyond the issuance date of the immigrant visa or the interview. This includes K and V visa applicants.

You must have at least one entire page blank so that visa stamped be affixed on it. If your passport is torn, dirty or exchanged for the old lost/stolen passport, the consular officer may scrutinize you more.

If the appearance of the applicant has changed substantially since the passport was originally issued (such as in the case of minor children with passports issued at birth), then a new passport may be required. Minor children should have their own passports.

Details in passport
Your name and date of birth as given in your passport and your birth certificate must be identical. The passport should reflect the correct name and date of birth of the applicant. If the applicant's exact date of birth is known, an estimated date of birth (e.g., 01-Jan-1960) is not acceptable. The visa is issued in the name given in the applicant's passport.

Married females
A married female applicant does not compulsorily have to change her name in the passport to her married name. Those applicants whose passports are issued in their maiden names will have their visas issued in their maiden names. Applicants should bring all current and former/expired passports with them to the consulate for their interview.

If you have changed your name after marriage, if you would like the visa to be issued in your married name, get the change endorsed in the passport before applying for the visa.

No first/last name
Some people in South India have only one name or all the names are written in the column of a given name or surname and other field is blank. If both the given name (first name) and surname (last name) are not present in the passport, the consulate will write whatever names are written in the passport as last name (even if that is your first name), and write 'FNU' in the first name column. FNU stands for First Name Unknown.

If you have more than one name but they are all written in one name, and if you do not want 'FNU' as part of your name in the visa, you should get your passport changed before applying for the visa.

Related links
India passport services