Here's an alternate process: I master in-place, in the project, rather than exporting a full mix and mastering in a separate program. This has one big advantage, which is being able to go back into the mix to correct problems that become apparent after mastering.
During mastering, you may become aware of issues that weren't previously obvious, such as excessive reverb or frequency imbalances. Addressing these in mastering is a kludge at best. It's always better to go back into the mix and fix those problems there. Having your mastering chain active whilst making those changes immediately lets you know if you're doing something right or just making things worse.
I use Ozone Advanced about 50% of the time, with FabFilter Pro-L being my primary alternative. Lately, I've been experimenting with Adaptive Limiter, which is proving itself to be a viable third choice. Often, Ozone is in there even when I'm not using its limiter, because I like its other modules.
My default preset is Dynamics -> Equalizer -> Exciter -> Imager -> Maximizer, all disabled with neutral settings.
I start with the EQ module, initially rolling off the extreme low end at 20 to 30 Hz. I always use the EQ module in critical-band mode, looking for obvious dips and peaks that might require mediation. If I find that more than 2 bands or adjustments greater than 2 dB are needed for correction, or if any of the corrections are narrow, then I dive back into the mix to see why that is, and attempt to fix it there.
Once I'm happy with the overall EQ, I next enable the Exciter. This is a dangerous module, because small movements can make everything immediately seem to sound better. But you're actually adding harshness whether you know it or not. Later on, you may become unhappy with the final master - if that happens, revisit the Exciter first and see if more conservative settings don't improve things. You get the biggest bang for the buck in the first and last bands. Band 2 will usually either have no excitation or will be set to a very low Amount, e.g. 1%.
Next is the Imager module, setting the first crossover to between 240 and 250 Hz and dropping the first band's Width slider to -100. Band 2 is either disabled or set to 5%, band 3 starts around 1.5 KHz and is set to 20-25, band 4 starts between 8 and 10 KHz and is set slightly higher. These are aggressive settings, just so I can hear the effect, but I usually back them off later. I do not use the Stereoize feature except in rare cases, e.g. solo acoustic guitar or piano.
Dynamics would come next, if used at all. I realize I'm running contrary to popular wisdom, but I am not a fan of master bus compression. To my mind, needing it is indicative of a failure in the mix process. Folks talk about "glue", to which I say "bah". It's a crutch for when you're in a hurry, an acceptable shortcut for professionals who are paid by the hour. As an amateur, I have the luxury of taking as long as I want for the mix, and I know I'm on the right track when the mix glues itself.
Lastly, the Maximizer. I start by setting the Ceiling. For aggressive rock, which is not my usual genre, I'll set it to -0.1 dB. More typically, it'll be -0.5 or -1.0 dB for clean stuff, and as low as -3.0 dB for jazz and classical. Again, I am bucking the popular trend here, but technically-speaking if your ultimate target is an MP3, you really should have that headroom.
It's worth experimenting with the modes. Everybody assumes IRC IV must be the best because it has the highest number and came along last. That's not necessarily true. Sometimes IRC I or IRC 2 works really well, although I'll admit that I'm most likely to end up using IRC III Balanced or IRC IV Modern. If the piece is very percussive, IRC IV Transient.
Character depends on the style and genre of the music. For my stuff, I usually stay between Smooth and Transparent. I keep the Stereo Link at 0% (again, contrary to popular practice). I'll try the Transient Emphasis to see if it helps, but it usually doesn't so I usually turn it off or use a low setting. As with the Dynamics module, Transient Emphasis is a crutch that shouldn't be needed in a good mix.
Finally, I bring up both SPAN and Insight and watch them as I adjust the Maximizer's Threshold slider. Because I'm not mastering for radio, I set Insight's loudness target to -14 or -13 and pull down the Threshold until I've found a nice compromise between the quiet parts being loud enough and the loud parts being quiet enough.
Keep in mind that all of the above are my personal preferences, and will not be suitable for everyone. If your genre is Hip Hop or EDM, forget everything I just said.