There's not enough space here to explain everything you need to know. But, there are some things you can do to improve your situation. One major problem with the computer is the deception of the color monitor and what is shows you vs. what you get back from the printer. Most people starting out work with this deception and disappointment.
"If you know the characteristics of the press, you can specify the highlight and shadow output to preserve certain details."
This is important, but it is only one piece to the puzzle. Other important things to consider are the type of paper to be used on that press. What Adobe is saying in the quote is, some presses can hold a 2% dot ( highlight ) and a 93% dot ( shadow ). Your color setting in Photoshop controls dot gain which is also important. Other things to look for in Photoshop images is the file's original RGB profile. Most printers want you to color correct and convert the images to CMYK. This is also important because you can minimize such things as color casts, low contrast, and total ink limits.
There is also the seduction of sending RGB files and letting the RIP do the conversions. Somewhat mediocre attempt at automating the process. I recommend against any type of automated workflow. As a designer you've become the point person on production ( whether you like it or not ). You are responsible ( you knew that already, I know ) for the final product getting to the customer the way they expect it and in most cases, beyond their expectations. Here's what I would recommend at this point:
1. Get "Adobe Print Publishing Guide"; it will give you some of the parameters I mentioned above and also discusses other print methods.
2. You cannot, in some cases, pre-determine the press characteristics on every job. The key is predictability of your workflow. Sorry to say, but approving a "soft-proof" on screen is not part of predictability. So, at a minimum, calibrate your monitor ( if you haven't already ). First and foremost, do not rely on your monitor, even a calibrated one.
3. Get a contract proofer in-house. This is a major investment that allows you to proof image files before they go to the printer and also are used as part of the file turnover process working with the printer. If the print vendor receives a contract proof with the disk, many questions can and will be answered upfront and will save you money.
4. Get used to the terms DPI and PPI. DPI refers to output resolution. A good direct-to-plate output device will require a 5080 DPI as standard. PPI refers to image resolution and raster resolution. Typical file PPI = 72ppi ( low ); 150ppi ( med ); and 300ppi ( high ) resolution.
5. There is also a belief that CMYK is the only print process. On the contrary. Take a look at silk screen and Spot color printing technologies.
Do not become overwhelmed with all of this information at once. It takes years of experience to become fully capable of producing catalogs, magazines, and other printed products successfully. Add to that that many print vendors do not have the answers. You have to find them on your own. Find a local shop that will allow you to intern a few hours a week. This will prove very valuable in that you will learn quickly what is required to get the job done right the first time. The key is finding a good shop that has a really good prepress department that really know what they are doing. Hope this helps, let me know either way.