Embed and/or outline when making final file.
300 dpi imagesAll fonts must be embeddedDo not downsample imagesDo not password-protect PDFs
300 dpi
300 dpiFlatten Transparencies
All final artwork should have a resolution of at least 300dpi. Most photos that are from the web are low resolution at 72dpi. Printed images always need to be at least 300dpi.
Please note that pixel-based images lose resolution when their size is increased.