- Accurate color profiling of any system is imperative. If you accurately profile your system then you will traditionally see on screen what is going to be output.
- Ask what your printer prefers for rich black. Every printer is different. They will have their own mix fo rich black. Use that mix for black when needed. Side note: if you accurately color profile your system and the app color management is set up properly, you'll get rich blacks in many areas. These can be okay to use if you don't know your printer's mix. The printer can convert but maintain numbers if they know what they are doing. if they don't know what they are doing, any rich black is better than none.
- Get color proofs where possible, especially for large jobs or those 6 and 8 color jobs you asked about. Printers have moved into the "internet" age as well and will often want to simply supply online PDF proofs. These are okay to check for drop offs. However, you can't color-proof a PDF. Ask for a color proof or Chromakey if you feel color is imperative. They can be FedEx'ed overnight (yeah they cost a bit). They are well worth it for some jobs.
- Develop a good report with all print providers where possible. So many issues can be corrected by a simple phone call or email before a job is run. If the print provider knows you, he's more willing to stop and check than
simply run the job and then re-bill when he has to rerun it.
- The mark of a good printer is not how well things go when there are no problems. The mark of a good printer is how things are handled when there is an issue.
I'm sure I've missed a thing or two but this is a general outline.
With respect to "test prints" there's really little you can do for many files. Unless you've got a very high end printer and you are creating files for digital presses, nothing you do in an office/home office is going to come close to a commercial platemaker and press.
I run prints through a simple monochrome laser printer (postscript level 3) to ensure alignment of objects if needed. Or to physically see text sizes rather than merely estimating based on the screen. Printing a page here or there can also assist in checking balance and readability from a distance. That's about as far as I go for "test" printing.
Each project is unique. It's difficult to give blanket guidelines for any "CMYK" printing.
If creating a booklet, brochure, or something which will involve die cutting and/or bindery I will make a miniature mockup in order to verify folds are correct and page placement is correct. Just bank sheets of paper folded and cut to match a scale model of the final piece. I then scribble on the pages of the mock up to indicate page direction and order.