Mixing

Listen to your music at moderate levels in your car or on a boom box.  This is how most of your fans will listen to it, and mixing at loud levels will fatigue your ears and distort the "true" sound.

Sometimes it's good to take a day off and come back to listen.  The same applies for mixdown.  Ears don't last very long in the studio!

As you review each mix, make sure you can comfortably hear all of the instruments.  Tweak the mix on a small pair of speakers at an extremely low volume.  Headphones are also very valuable at this stage, but don't base your final decision on them.  You should be able to pick up each instrument even at this level.

Know when to quit for the day.  You're better off quitting a session early when you're tired than wasting time making a bad mix that will have to be redone anyway.

Listen in the studio to CDs you're used to hearing on your home stereo to get an idea of how the studio's system sounds.

Determine a band spokesperson ahead of time.  An engineer getting five different opinions on how to mix will grow tired and might cause him/her to rush through the job.

Once you have selected an engineer (or a producer) to mix your recording, have them do the first mix.  Their ears are better trained than yours.  Try to keep an open mind.

Think about the songs as a whole and not just the individual instruments.  Otherwise everyone will want their instrument louder in the mix.

If mixing somewhere other than the recording studio, make sure you use the same speakers.  if not, the mix will sound completely different.

Count on and budget in unforeseen delays