Consulates send people home for the same short list of missing items. Bring all of it.
- Your current passport, even if expired.
- Completed application form, filled online and printed.
- Recent photos meeting the exact spec. Photo rejections are the number one same-day failure.
- Proof of legal status in the country (visa, residence permit).
- The fee, in the exact payment method the consulate specifies. Many take only money orders or cards, not cash.
- Prepaid return envelope if they mail the new passport back.
- Photocopies of everything. Consulates love photocopies.
Sources: U.S. State Department
For a consulate passport renewal, bring the full folder: form, photos, fee, and photocopies of everything.
Check the consulate's holiday list too. Showing up on a home-country holiday to a closed office is a classic. Book the appointment, gather the folder the night before, and arrive early. Renewal appointments are routine; getting sent home for a missing photocopy is not.