My engineering skills are on the very remedial side. I'm fine in terms of getting good recording levels. Yea me.
 
But I'm having trouble adjusting headphone levels of individual tracks when recording myself. I fumble around lowering, raising, Sonar's volume, gain, and the Scarlett buttons, but since I don't know what's delivering what to where...lost. The result is that right now I'm recording acoustic guitar but it's overpowering in the phones, and can't lower the monitoring level in the phones without losing the other key tracks' volume also.
 
Seems that it might be easiest if I could get help from someone with a Scarlett or other Focusrite. Any patient, compassionate users of said gear?
 
Humbly and stumbly,
Bodhi

I find it easiest to set the monitor level of the track I'm recording through it's input channel in MixControl, and send all of the other tracks I've already recorded, and the click track if I'm using one,  to the Master bus and send that to the Scarlett Monitors 1&2.  Then I can control the level of those tracks using the volume control for that bus in MixControl, separately from the volume of the track I'm recording. 

One simple thing I often do, which has absolutely nothing to do with MixControl or even the interface itself, is to set up a "monitoring bus" and add sends to that bus.   When I'm ready to record on a particular track I enable the send which adds volume to the track I'm recording without changing anything else in the mix or routing. 

I use mix control with the saffire pro 40.  While it has different hardware options, the software may be the same.  I have occasionally been baffled by it when setting up mixes etc...  The easiest way to think of it is that mix control is your monitor mixer and sonar is the daw.
 
https://www.youtube.com/results?search_query=focusrite+mix+control+tutorial    This is a simple youtube search 

Thanks, guys. All of this is helpful. Will digest!

The best video I have seen to date on Saffire's MixControl. 15 minutes, but worth watching.

https://m.youtube.com/watch?v=M1avPHhiGw8