There are really no big secrets here…just make the best mix that you can make! Don’t worry about any specific amount of headroom that you may have read somewhere on the internet. Whether the track has 3dB of headroom or 20dB doesn’t make a big difference. Any mastering engineer will adjust the gain of each track to suit their system anyway.
Having said that, here are 2 guidelines that will result in dramatically better masters:
1) Make sure the mix isn’t clipping. Seems obvious but you’d be surprised by how often it happens. If it is clipping, the easiest way to fix this is to put a trim plugin on the FIRST insert of your master bus (before any of your master bus plugins). Then reduce the gain until the mix isn’t clipping any more. The reason you want to do it this way (rather than just turning down the master fader) is to ensure that none of your master bus plugins are clipping internally.
2) Turn off any brickwall limiter your might have on your master bus (L2, Ozone, etc). A buss compressor is fine if it’s an integral part of the mix. But any processing that’s there for the sake of volume is better accomplished in the mastering phase. We have better tools to deal with volume and you’ll invariably get a louder master if you turn those plugins off.
If you have any other questions about how to prepare your mixes, don’t hesitate to contact us.