I use VU meters running in 
Reaper as a visual aid for knowing what my mix is. I run a seperate VU for mics and background music.  I try to keep them almost even, with a bias on the singer.
Take a look at this picture to get a better idea.  The red arrows point to stuff.  Mic is mic, BGM is back ground music.
http://shup.com/Shup/253056/109111214313-My-Desktop.png