In the arrangement, you focus on the range of your instruments.
You can use the classic soprano, alto, tenor, baritone, and bass
technique; or you can create your own system. The important thing
is that you know what range each instrument falls into, and you fill
each range equally. Get really creative by having instruments stray
from range to another, but you must maintain constant awareness of
coverage. In other words, if your melody moves from the soprano
range to the alto range, you may want to incorporate a harmony that
fills the soprano range during this period of time.
Layering In The Mix
In the mix, you pay more attention to frequency range. You can
separate your mix into highs, mid highs, mids, low-mids, and lows,
for example. You determine what tracks will fall into each range, and
again, the same rules apply. When a single track drops or rises into
a different frequency range, you can use an automated EQ or
effect, to fill the missing space. With mixing, the important thing is to
recognize each range individually, as you move through the song.
By maintaining this awareness you will automatically use techniques
to maintain even coverage. This will give your mix greater presence.
By utilizing all of these layering techniques, your sound will literally
jump of the speakers. One of the typical problems that amateur
producers have is that their recordings sound like their ‘coming from
the stereo’. If you listen to a great producer, you will notice how their
music ‘fills the room’ with sound. These techniques will get you there.