On this slow time musically for me, I have done a lot of experimentation with compression and limiting. I found that I get the best mix by using almost all my compression before the master bus. On the master, I use a multiband but all ranges are bypassed except the low-mids, which I squash a little more. It really helps bring the music out.
I also use compression on the individual tracks, attempting to get the best out of each track by getting each of the faders as close to nominal as possible (0db) without the master bus doing massive limiting. And my master bus is pretty much always set on 0db. It took ALOT of playing around to get close… and I still have a ways to go, but I’m seeing something for the first time that seems to be working for me.
I’m using this more as an exercise in how to compress/limit … it’s just a rough demo of voice/piano. Your answer I think is giving me some nice insight into the process. Can I follow up with another question or two, Professor? 
You can look at the meters in your track or whatever plugin you’re using. For that particular track. You set it so that the meter just hits 0db on the VAST majority of peaks.
If you can picture the track meters without limiting on them, the gain reduction meter would be inversely proportionate to them. Personally, I don’t use “full on” limiting, where there appears to be no movement of the track meter and its just buried at 0db… I’ll play with the track levels until I get limiting…err… about 70% of the time on choruses, and 50% of the time on verses (very loose estimate). This still provides a bit of dynamic range.
But it takes a ton of playing around. Seriously! I’ve had to shift > select all my tracks and pull them back more times than I can count so I’m not smashing the hell out of my songs. Once you get it, you’ll see that it’s a very delicate balance, but you’ll start to feel it when you’re close.