05 Source Sounds Make sure that any audio or samples that you're using are clean and free from static, pops, crackle and hiss - unless you want them to sound that way that is!
Although there are loads of plug-ins dedicated to cleaning up dodgy samples and rough sounding audio it's going to eat into your recording time if you need the engineer to do this.
It can also disrupt the flow of the recording and take away your inspiration.