Mark
I'll try and take a screen shot of a "typical" session for our band (4 piece- drums, bass, guitar, keyboards, 3 of us sing)
The more you can bus to aux sends the fewer plug-ins and the lower the demand on your CPU. I have an 8 core MacPro with 10 GB Ram, but Digital Performer can only use 2 GB (until they release the 64 bit version... rumored this summer), so while I have plenty of CPU resources, the RAM is the bottleneck. Plug-ins that look ahead (like Ozone, or some compressors, and most all pitch correction programs, really can hog the RAM. I'm seriously considering adding a UAD-2 and letting it handle some of the compression and EQ duties... though I believe they are proprietary to UAD plugs... but that might help
vocals- If I have a "thin" voice, that EQ won't quite fatten up I can either duplicate the track and put a slight delay on the 2nd to thicken things up, when i get the right amount of delay (which for this is usually quite short) then I might add some verb to the original track, just enough to give it some 'air' but not enough to start sending it 'backwards' into the mix I like the lead vocals to sit on top , but not 'out in front' too much (I don't want it to sound like someone was singing kareoke style... LOL).
and that is the one pitfall (IMHO) of reverb, it's very easy to create too much 'depth' and suddenly have it sound like everyone in the mix isn't in the same room/stage.
With BGV's I may use 2 mono aux, sending each of the BGV's to each, panning the 2 mono aux differently often both to one side, but spaced ( say 17 and 30... etc), seldom will I pan one left and one right as I want the lead vox in the middle, and the BGV's (again IMHO) shouldn't be standing right next/behind the lead0 To each au i will add delay, and sometimes a slap-back on one and a short delay on the other aux- which seems to add some body to the overall BGV's. The original tracks may be used as a dry track,or more often I set the output low to almost quiet so the aux tracks are what's driving the sound of the BGV's
Do you have favorite CD's/LP's that you are very familiar with? Listen carefully to those and pay close attention to placement as well as the different instruments- I like Steely Dan's Aja, as well as the recent Robert Plant/Allison Krauss CD's , great mixes. Early Beatles (Revolver, Rubber Soul) are good examples of compressed drums0
and to carry it a step further, record the song so you can open it in a session and slap a frequency analyzer on the stereo track and see see where the different instruments 'fall', there will be overlap, but you should see peaks that are the signature of certain instruments, like the kick, the snare, the bass. If you have a broadband parametric start cutting frequencies out to see/hear where the different instruments (and voices) are most prominent- this might give you a stronger insight into the subtleties of EQ.
Think of it as sonic skulpting, and you have to learn your ears, I might hear something completely different, plus, in the world of net sharing, I'm listening to your tunes in a completely different environment, so right off the line things have changed
and about the brass... something had a brass sound (on my listen) earlier in the song, maybe a synth pad.... but it was brighter and seems to stand out a bit more than the rest