Make your picture box background color white, rather than none.
Be careful as you layer objects, often the top most text will "spread" based on what Quark sees beneath it, even though it need not spread. Printing your file as seps will reveal problems.
Be aware that colorized bitmap tiffs will not trap to a background color.
Use facing pages carefully - Laying out a facing page document with crossovers will require additional work at print time; either moving pages to reflect "printer spread" pagination or saving your pages as quark eps files for imposition for press.
Making black drop-shadows will often cause the top most type to overprint.
Use your "collect for output" option to save your files for the Printer.
Be aware that you must gather your fonts manually.
Avoid using the old "Pasteboard" xtension. If you have this; consider using the "Pasteboard Exterminator" extension instead.
Make your booklet cross-overs as two items rather than one whole piece.
Avoid auto page numbering where possible.