If you are using any MIDI tracks or DI guitars/bass with amp sims, please follow these steps. It's always best to have the MIDI / DI plus the printed sounds that you were working with. That way I can hear what you heard and decide if it's usable. If not, I can either enhance it, or replace it easily.
MIDI and DIs give me maximum flexibility, but having to start with only those means I have to create a tone completely from scratch, without knowing what you were going for. That's essentially producing and not mixing. So, please always include the tone you got, so that I get an idea and a reference of the sound you came up with for that specific part.
Always use the same sample rate and bit depth you're already using in your session. So, if the session is 44,1kHz / 24 Bit, for example, print (export) all of your files exactly like that.