Alright, welcome to Earth. There are no magic fairy princesses and no one I know keeps cinnamon and sugar in the same shaker anymore. Audio mixing has nothing to do with magic at all. In my opinion, audio mixing has nothing to do with fidelity at all either. All that was done earlier. To be honest, I don't even know what fidelity means either.
What I Think Audio Mixing Is
I think audio mixing is a time for me to maximize the intensity of a song. There are all kinds of tricks that can be done during the mix that can greatly add to the emotional intensity of the song. By using these tricks, maybe the listener doesn't notice, but I have a feeling they'd notice if you played them the version without intensity added.
I want to make it clear that mixing is a creative thing in my opinion. It's my time to add to the music in a way that makes both the artist and the listener happy. Mixing is not a time to make the song I'm doing right now sound like the mix of some other band. (This is impossible, by the way. While it's good to reference great sounding records while you mix, there is no way to clone a sound. In fact, bands that tracks with the same micing scheme sound dramatically different from song to song. So it's impossible to take a different song and 100% match some other song) Mixing is the time to take whatever tracks we have and make them work together in a way that makes the song the best it can.
Think In Terms Of The Song
Now you can see the direction I'm going here. The focus is THE SONG. It's not about understanding complicated electronics principals. It's not about understanding complex acoustics either. It's about being able to manipulate the tracks so that the entire point of recording this particular song is made entirely clear.
When you get the notion of mixing being about compressors, eqs, or whatever out of your heard and start thinking about the song, you'll see this recording thing in a whole new light.
If You Are Having Mixing Problems...
So let's assume you are having mixing problems. If you've actually read this far down into the article, I'm going to assume your mixes do need some work. Let's just say you put a mix in your car stereo and something doesn't feel right. You can't quite put your finger on why this mix sounds like shit, but you know it does.
Now I know that when you are simply recording a demo for someone, you need to be a gynecologist. You can't sit there and play around with their goods in a way that is pleasing to you. You are there to objectively help solve (purely engineering) problems (phase, acoustics, frequency response, choosing the right microphones) with their most sensitive of areas and it doesn't matter if you like the song or not, right? Well.... that depends.
The Big Picture
Here is the big time lesson of this article. If you screw this up, you'll set yourself back 2 years in your recording development.
#1 Let's assume that mixing is a creative process with the sole purpose of making the song more exciting or more emotionally intense for the listener.
#2 Let's assume we are working with a song that flat out sucks in your opinion.
How can you possibly make a horrible song exciting with delay, reverb, and volume automation? Explain that one to me because I think YOU CAN'T! A shitty song is a shitty song. A shitty song should never be recorded anyway. I realize that one person's crappy song is another person's favorite song so there is some subjectivity that needs to be accounted for. However, if you feel absolutely nothing in the song, I don't think you are the right guy to mix that song, because there is absolutely nothing you can add to the music if you don't believe in the music anyway.
If you think a song sucks, don't mix it. I realize that this is an oversimplification and doesn't factor in the fact that we have bills to pay, recording gear to pay for, etc. However, there is no way you can possibly do your job as a audio mixing if you think a song is total dog vomit.
If you have already agreed to do a project and end up recording a terrible, terrible song then finish the gig like a pro (and basically take it in the ass). However, don't make the mistake again. Don't record crappy music! You'll find that your mixes sound 100 million times better when you catch yourself singing along.