They place and control each element with deliberate focus

Start with the end in mind

When you are mixing for a church, concert, online feed, or outdoor gathering you must first start with the end in mind. How large is the venue? How many in the audience? What audio treatment are installed or naturally occuring? What are the limits of your hardware? How controlled are the audio sources which may bleed into other channels in the mix? How much reverb or echo will the space require to feel the fullest? How will the mixing booth sound differently from other spots in the room?

Master audio engineers start with all of these questions and more before they dial in a sound. The most talented engineers will answer most of these questions in just a few seconds as they walk around the venue. With the experience they have acquired, they will quickly make overall adjustments and then start placing the channels as desired in the mix. The key here is that more experience results in near instant determination of how they will achieve their end goal for the space.

Example

Since we want a contemporary christian rock mix, we will keep the volume slightly louder, slightly higher bass, and heavy guitar and drum presence in the mix.

As you build up your experience, you will begin to start with your end goal before you adjust any settings. A thoughtful reflection on the space may go something like this: We have 300-500 gathering, large space, no audio treatment in room which will cause artifacts for performers, audience, and standing waves for bass near walls. Hardware is limited by 20 channels and 10 processors. Stage audio with monitor mixes will require tight cardioid vocal mics, the space will need some reverb but not as much as a treated room. Sound pressure will need to be monitored for low end, sound level monitored for mid-high end. The band is made up of 2 vocalists, 5 instruments. The drummer will not be using a drum cage for controlling sound.

Placement

Now that we have described what we want for the mix in very general terms and we have considered the space, treatments, and hardware limitations, we are now ready to set our mix.

Start with the vocals. Vocals should be bold, crisp, and given healthy dose of reverb. If possible, restrict the reverb to the higher end to avoid muddying your low end in the mix.

Next, mix the lead vocalist' instrument. Depending on the shape you want, you might set EQ with more energy in the high end or a broad fullness. Tend to use subtractive EQ. Don't boost, or drag the EQ shape upwards. Cut or lower EQ to help avoid slight phase changes in your audio. As technology improves this becomes less of a concern, but the best engineers tend to only lower not boost EQ.

Continuing through the list you may want to set the drummer, then the bass, and then the rest of the band. In my article on compression, I will go into further detail on treating with a type of compression that is best for each channel. Every channel should have compression when possible. Remember that simply having a compressor on does not mean it is always affecting the mix. Compression can actively shape a channel or may be used as a safety net to limit volume in extreme situations with spiked inputs.

Color and sonic shape

Now that you have begun volume control with the use of gain and fader, you can now work towards the shape and overall tone of the mix. Think for a moment how you would describe your best mix. What tone are you looking for? Write it down until you are able to identify the overall tone instinctively. You want a thick bass? Give a nice boost 100-200Hz for the punch and compress the low end so you have a full bass without overwhelming the low end. The guitars can be separated in LCR mixes to help listeners distinguish between similar sounds. 

After you work your way through each individual channel, you now have the privilege of fine tuning. Your mix can almost always sound better, depending on the processors and control you have to dial in settings. Don't get comfortable! You willingness to review and revisit settings is a critical to finding the mix you really want. As you do make changes, do your best to compare before and after small adjustments to verify it's achieving the sound you want. Don't be afraid to try new tools, but remember that more ≠ better. Audio quality can suffer from multiple processor chains, so be mindful of the results of your labor and be willing to reduce or change settings on processors when your adjustments prove unhelpful.