A clean print file is less about secret settings and more about removing ambiguity before production begins.
Ask for specifications
Request the preferred PDF standard, bleed, trim, color profile, image resolution, ink limit, spot-color policy, and proof expectations. Specifications beat generic presets.
Inspect color usage
Find unintended RGB objects, duplicate spot colors, low-contrast text, white overprint, four-color small type, and black builds that exceed the ink limit.
Export and preflight
Export a PDF using the agreed standard, then inspect page boxes, separations, fonts, image resolution, transparency, and output intent. Opening the PDF is not the same as preflighting it.
Communicate intent
Include a marked-up reference when color hierarchy or finishing is important. Tell the printer which elements are critical and what kind of proof is approved.