Avoid rotating graphics in Pagemaker; rotate them in Photoshop instead.
Be aware that Pagemaker will not trap graphics, only type or drawn objects. Also, "special" lines (Dotted, dashed, etc) will not trap either.
Link your graphics, do not embed them. Pagemaker will embed them up to a certain size. You can change this in the preferences so that it links all imported graphics.
Eliminate all items that are on the pasteboard area.
Run "Preflight" in the Utilities menu under "Save for service provider".
Run "Save for service provider" under the Utilities menu to gather your files for the printer. Be aware that Pagemaker may not gather all your fonts, so check for them carefully.
Make sure your windowshades that contain type don't extend beyond the edge of the page.
Avoid using facing-page documents where unecessary.