For digital jobs, always make sure that you are working in CMYK color space and not RGB.
Always make sure you include all the linked files to your layout including the fonts. There are thousand's of fonts and not including all the fonts will slow up printing your job.
Make sure you include the version of the software you are working in.
If you sending in a Acrobat PDF job to be printed, make sure you use "Press Quality" for your setting and include bleeds/crops.