Thanks for the feedback everyone.
We are not gigging yet - haven't figured out the live setup yet - it's difficult to know what's acceptable onstage for largely computer/synth based music.
Now I'm no expert on production - there are professionals visiting this board I believe, but here goes:
I find the panning of each track helps the clarity enormously. I tend to pan the bass sounds in the middle with the higher ranges such as guitars/vocals/synths panned left or right.
As far as effects goes, I generally compress vocals and bass ranges and add reverb to snares/vocals/synths/pianos etc. but not too much.
Also, make sure you dont have all your tracks at a high volume because you lose control over the mix.
I picked up most of these tips from Computer Music Magazine and by browsing websites. Also, if you keep doing it long enough you will gradually get an ear for whats right.
Trust your own ears is the best policy.
There are probably loads of other small tips that others could contribute (invitation).