Well, my idea won't work after all, just tried it.  Sonar "locks" the mix file being referenced by the Mastering Track, so you can't export a new mix.
 
What's the consensus on placement of the mastering EQ (provided we are talking extremely minimal tweaks)? Should the EQ be last or rafter before the limiter?
 
     Sonic

Pesonally, I find it helps to keep the distinct processes seperate: so I have a file for recording, I export stems into a new file for mixing, and finally import the mixdowns into a new file for mastering.  When I try to do everything in one project file I find I lose focus on the current task, and get distracted by posibilities up and down the chain.  I have worked in a single file from recording to master, but the results ain't as good.  Having said that, It might well depend on the sort of music you make, if it's all soft synths with little audio recorded in real time then the prehaps the 3 stage process is overkill?

Mixing with latency-inducing plugs can cause problems, although if it is sputtering your system that is another argument for using a stereo editing program.
 
Or get a SSL desk.  A couple of pros I know won't mix unless it goes through the SSL buss comp, with speed of light hardware latency!

jerrypettit
On a related note, I'll put a CD together when it all sounds good, burn a copy and play in my car...and without fail I'm fiddling with the volume knob from song to song--even though each song has used pretty much the same mastering plugins and is limited to -6dB.  
 
How do I get these songs to sound at the same appropriate volume after printing.  My ears aren't getting it done.  I assume there's some kind of "metering plugin" that I'm missing?

This is where "perceived loudness" comes into play. Specifically, a metering plugin that attempts to show you how loud it subjectively sounds to humans, regardless of objective RMS and peak levels.
 
SONAR/Cakewalk has such a meter, albeit a simple one, built into its Adaptive Limiter. It shows a horizontal line over the its graphical display that represents loudness units (LUFS). Adjust the levels of each song so that they fairly closely match where that line falls, and they'll all sound pretty close when you play them back. You don't have to use AL for limiting if you have a preferred third-party limiter, you can just insert AL for its LUFS graph. 
 
If you want to spend some money for something fancier, the best loudness metering I've seen is iZotope's Insight. There are, however, many capable plugins for much less money, such as MeldaProduction's MLoudnessAnalyzer.

Many good suggestions already posted.  You'll find that as you learn & progress your methods may likely change ( definitely try more than one approach &/ or daw)
I would only add that that you should export your source files at best quality or of the project settings, keep them organized with several backup copies. That way you can easily remaster them at a later date using any method & w/o fear of losing them if they are in the projects audio folder & it somehow gets deleted or corrupted.
If not already mentioned first get a few reference mixes, try the free mastering services like LANDR to hear what that results they give you. ( not always good but can give you a bit of insight when first leaning)
Select 1-2 tracks & have them professionally mastered, keep them as comparison reference mixes when doing your own masters.
Also don't get discouraged, chances are it will take quite while before you handle on the process & start making masters you're satisfied with.

My approach may not be what the "masters" do, but it works well for me and old style "traditional" country music.
I get great comments and returning customers.
 
I record all the tracks.
Do what is needed for each individual track
Bounce all tracks to a new track (mixdown)
"Master" the bounced track with Izotope Ozone 5 or 6
Export the mastered track as a 16 bit 44.1Khz wav file. 
Burn audio CD's with Nero BurningRom application
 

I mostly use the all in one approach because my targets are not hard copies or made into an album. 
 
Personally I think the ability to change the pre master and hear how it will sound after the mastering plugs is a benefit.
 
The only time I have exported from a project to a separate master program was for hard copy albums or in using multiple staging for volume/limiting/compression. I wouldn't have had to do it then, but it was easier to add complex chains to a separate project and keep it all organized since I could dedicate an entire project to it. I mostly mix soft acoustic, so I'm not into that because it usually isn't necessary for me. I dropped out of the loudness wars a long time ago.

SonicExplorer
Well, my idea won't work after all, just tried it.  Sonar "locks" the mix file being referenced by the Mastering Track, so you can't export a new mix.
 
What's the consensus on placement of the mastering EQ (provided we are talking extremely minimal tweaks)? Should the EQ be last or rafter before the limiter?
 
     Sonic

EQ before limiter. Limiting should be the last process and EQ should be the first because cutting or boosting frequencies will affect the overall level.

I keep in my master buss: LP64 EQ, LP64 Multiband comp, Voxengo Elephant, Voxengo span.
 
When tracking and mixing, I keep the master buss FX bin bypassed, so that I don't' have to deal with latency issues from the LP plugs.  When mastering, I just turn on the FX bin and adjust the plugs.  I usually aim for about a -8 dBFS RMS.
 
There may be better, more pro ways to do it, but there is not an easier or faster way.  And since I'm not being payed to do it... easy and quick it is!
 

For quick results, take a look at AAMS Auto Audio Mastering: http://www.curioza.com/ - there's a free and paid for version.
 
I tried out the free version on a couple of tracks and the results were about the same as I got from LANDR.
 
There's hundreds of genre presets, so it's likely that given a bit of trial and error you'll get something close to what you're looking for.
 
Like all auto-mastering software, it makes generalised decisions so it wont have the various tweaks you might want in at specific points in some tracks. I did however find it useful as an additional reference track when doing the final master.
 
M.