There are lots of different
ways people have gone about trying to get the
most out of chip music, and a good way to
learn is to download some NSF and/or SID files, and listen to
each channel separately. For instance, you'll
notice in some NES music, the triangle and
noise channels work together seamlessly to
provide the music with a good drumbeat and
bassline. For example, you could make a
triangle channel instrument that uses the
auto-portamento effect at a high-rate, put a
note in and give it a space or 2 depending on
the tempo then put a note off or your
bassline in the triangle channel.
Using the non-looped arpeggio
effect, with the first arpeggio value at $C
will provide a short percussive sound at the
beginning of a note.
Using the noise channel along
with drum samples will greatly alter the
sound of the drum, with a snare sample for
example you could give it a longer decay and/or
a brighter quality. Try using arpeggios (looped
and non-looped) on the noise channel.
Most importantly, try to
develop your own style and techniques. That
is what makes music worth listening to. But
that will happen without you really noticing
it, anyway. :)