It's a tricky-sticky issue, mastering. We want great results for as little money as possible.
One of the first places to start is the monitors. I've been told by different sources that a pair of "true", accurate, and energy/driver efficient monitors with 8" woofers are the first place to start. I won't begin to make any recommendations in this area because the discussion would go on ad infinitum. Another important item would be a single flat response small 3-4" monitor for cross referencing your mix/mastering results.
Given that the monitors are accurate and tell you the truth about your mix (for good or ill), it is important that you are actually listening to these monitors and not to any anomalies in your mixing room. Solution-- acoustical treatment and accurate measurements with frequency response. Tune that room and calibrate, calibrate, calibrate!!
You could actually do a nice job with DP's built in plugs. Yes, there are better plugins out there for mastering, but it's going to take some amount of ka-ching no matter which way you go. You may want to check the free plugins thread for some respectable plugins that are actually better than those included in DP. Here is an example of some useful FREE plugins-- but these do not constitute the totality of the kinds of plugins one would need. Neither are there any guarantees that you get what you pay (or don't pay) for:
Magnus Digital Reverb
http://www.smartelectronix.com/~magnus/
Free SSL from Solid State Logic!!
http://www.solid-state-logic.com/resour ... lugin.html
LFX Multieffects
http://www.luxonix.com/home/en/products.html?id=lfx1310
Frekoscope Spectrum Analyzer:
http://mdsp.smartelectronix.com/ffttools/
Honestly, it would be worth investing in good mastering suite. You should first determine what kind of results you want. Bias Peak is one example of a standard yet versatile suite of plugins. IK's T-Racks 24 is a different sort of suite of mastering plugins with an emphasis on analog modeling. UAD-1 is another example of analog modeling based upon popular gear from Universal Audio, Neve, Oxford, Pultec, and other reputable names associated with high end vintage gear.
To begin to develop an "ear" for mastering detailing and fine tuning, you might want to fly in (import) a well mixed, well mastered commercial track into DP (muted until needed) that appeals to your ears viscerally. Compare that mix to your own mix even as you mix. Fix everything you can in the mix because it will make the mastering process much easier.
There's a whole other element some people swear by, and that's analog summing. Some people find that this process adds character and "depth" (and depth of character) in a way that working entirely inside the digital realm cannot. It is a matter of taste-- and money, of course.
Okay-- so you ask "what do all these terms mean, for crying out loud"? I hear ya.
Bibliography:
1. Mastering Engineer's Handbook (Bobby Oswinski)
2. Recording and Mixing from Demo to Finished Master--- DVD tutorial (pub. Universal Audio)
3. SMART Guide to Audio Mastering (Bill Gibson)
4. Mastering Audio: The Art and Science (Bob Katz)
5. Basic Mastering (Paul White)
There are also numerous tutorial books dedicated to specific mastering software suites.
Mastering is one the most underrated and misinterpreted steps in audio production. I've seen mastering engineers do things I never thought possible with a stereo mix- like make a vocal part sparkle without making other instruments harsh, giving considerable punch to lower frequencies without compressing the life out of the mid-range, etc. Yet, some things just can't be fixed in mastering and must be fixed in the mix. Other things cannot be fixed in the mix and must be fixed during tracking.
It always takes a couple of projects to compile a list of things that you would "do differently next time", if you know what I mean. Mastering is more art than science, imho, and you are a brave soul for venturing into this territory!
One consideration and valuable lesson is to find a mastering engineer who will let you sit and watch the process. That would be worth doing at least on your first (your next, or on one) project. Don't yack at him while he works (mastering is quite an inward and wordless a task), but take notes and write down your questions. During a break, pose your questions. I was fortunate enough to observe the process with someone who uses DP religiously.
Well, there's a start for ya. Good luck!!