When it comes to a great sounding mix, one of the biggest steps you can take to ensure high quality is to make sure your master channel output is not hard clipping (in the red.)

When you have a master output that is hard clipping it can cause unwanted artifacts such as harshness, muddiness, crackles, damaged dynamics, ruined transients, & less clarity.

Simply lowering the volume going into your master channel can instantly improve your mix!

-6dB of headroom going into your mix sum or master channel is ideal, but you could get away with as loud as -3dB if you really wanted to.

It's best practice to have the headroom going into the mix sum/master channel rather than turning down the channel fader on the mix sum/master fader.

That's because that fader is post inserts & post channel input. So the damage has already been done. The input has already been clipped & the clipped signal is entering all the plugins that way.

The most common way is to group all your mix channels (not including AUX channels) together & lowering them so the headroom is going into the mix sum/master channel.

It's an instant fix!

Some people may take an easier approach by just adding a trim plugin as the first insert on their mix sum. That can work too, but you may find that lowering all your mix channels isn't too much extra work than a trim plugin.