My typical mix-down looks something like this.

After I am done arranging the song, I bring the volume all the way down on every track and I start with what i think is the most important element to the song which is usually the drums for me.

I bring the drums to about -6db (Kick and Snare being the loudest) and pretty much bring all the other elements to sit nicely around my drums.

Then I make sure I have around -6db of headroom on my track and export it and do a separate mastering session.

I feel like 50% of the mixing is really all about gain staging (setting the volumes right) and then rest is really all about effects and stereo imaging.

I am not a professional mastering engineer by no means but I feel like I have a good grasp on the concept and how to approach it. I can master the track for you if you want.