Bring the passport, the employer's offer and duty description, and education or licensing records specific to the profession. Include any prior US travel or visa history. The consular officer needs enough evidence to assess the same TN eligibility questions a border officer would later review.
Treat the file as a complete eligibility package
Avoid submitting a thin or generic file on the assumption the consulate only checks formalities. Ask the employer for a duty letter that matches the actual work, not a template. Gather credential evidence relevant to the specific listed profession, with translations where needed.
Keep a copy of everything submitted, since the same documents will likely be needed again at the port of entry when admission is sought after the visa is issued. Treat the consular file as a complete eligibility package rather than a formality, because the officer assesses the same substantive questions a border officer would later review. Bring the passport, the employer's offer and duty description written for this role rather than from a template, education or licensing records specific to the listed profession, translations where needed, and any prior travel or visa history.
Keep a copy of everything submitted, since the same documents will be needed again at the port of entry after issuance. A thin or generic file submitted on the assumption that the consulate checks formalities is the most common avoidable delay in this sequence.