On the mastering side, I suggest if you don't have any extra money to spend for better Spectrum Analysis plugins like Sonalksis Stereo Tools or an all-in-one Mastering tool like iZoptope's Ozone, then you CAN use EQUO for analysis, followed by Fruity Multiband Compressor to do some multiband Limiting after using EQUO to even out any anomalous EQ spaces, ie. cut areas that are overpowering the mix and boost a few key EQ areas (like the above 2.5kHz area to give some "air" to the mix when it lacks that top end). Much mastering is, as already stated, genre-specific, but the actual tools are mostly industry standard: Analysis followed by EQ followed by Limiting.
I actually use Sonalksis Stereo Tools followed by their wonderful MultiLimiter followed by another Stereo Tools to make sure the changes evened out the frequencies. I do still mix and master by ear, but this setup allows me to reference what my ears are hearing and improve the frequencies for better playback on alot of systems. I usually finish up with a Sonnox Oxford Dynamics set to Limiter and maybe a little Warmth to polish the sound, or I'll be trying my new Ozone out for that duty on some tracks. There are alot of Mastering plugin companies with plugins which can do these duties, T-Racks, Sonnox, Ozone, Sonalksis, Antress, Voxengo, Kjaerhus, and a number of other companies, some even providing free versions of their plugins. The key, in my opinion, is to find a really good analysis plugin and follow it up with solid EQ, then finish with good multi compression/limiting.
