There's no real instant answer to this I think. Levels are so much more forgiving than they used to be back in the days of analog. In general, though, levels should always be maximized to avoid introducing any unwanted material into the recording. We do cover digital recording levels in several scenes - recording Vocals, A Live Tracking Session, Computers and Digital Audio, and also in Mixing. We will be opening up these forums to include discussions on this and other topics as soon as the entire series is released. Plus there will, ultimately, be a premium forum for live chat with Alan. Others may well post their thoughts too here so keep checking back in.

Happy Recording!

Hi
Heres a few tips for you;
1. 0dB is not something to be gained but something that you should steer clear of, the recent changes by the recording industry has already lowered this to a max peak of -3dB.
2. You need to understand how to create a sound field, compressing various parts to control them and when you are happy they will fit in the recording set the level.
3. The positioning and levels are a matter for taste of the song in question and does not have a general rule

If you want to see how the material fits, listen the AP's recorded material, examine the way it has been thought out and structured, and keep on examining until you think you understand then have another listen

If in doubt pay a professional engineer for his time and let him look at the mix