proper EQ, proper mixing
dont overdo on effects
group channels by instruments
eg: drums, synths, percussions, pads, misc, etc,
proper compression, proper limiting
on the master channel i only use a single limiter
all compression and EQ is done separately for each instrument, or each channel
but it all depends on what you want to achieve, since im more on electronic dance music
but most important thing is : PROPER EQ!
hope this helps