When setting up your audio for mixing it is important for you to label your track by instrument and take. Make sure that all tracks are finished with the editing process and do not need fixed. You should bounce all tracks down so that they all start at the same point and end at the same point. This will make it quicker for us at Twenty/20 to follow your song structure. Leave all tracks without any processing (EQ, Compression, Reverb, Limiting) unless that track in specific needs to sound like that. Keep all volume levels at -6 dBfs or 0 in the analog world. Don’t apply any pan as well. This will leave us with a clean slate to provide you with our expertise in mix engineering.
When prepping your files for mastering, don’t apply any limiters or an sort of mastering chain on the stereo bus. Always leave some headroom for the mastering engineer to work with; the standard is to leave -6 dB. That will leave plenty of space for any EQ boosts or processing that will help improve your song or album. When mastering the engineer will want to work from bounced down stereo mixes.