Leave the master fader at 0. You can pull it
down, if you want to, although this is sloppy mixing, I sometimes do it.
You need to understand the difference between mixing and mastering. You are bouncing a final
mix of the song, as long as everything sounds corrects in relationship to the other tracks (in the song itself), then it's good. Do not concern yourself if it is "loud" at this point. The goal here is to make it sound like what you want it to sound, that is, the vocals are where you want them to be in relation to the guitar, the piano is panned and as loud as you want it to be in relation to the bass and drums,
everything is where you want it to be in relation to everything else. This is your mix. Bounce that.
You'll be wanting to have more information than that, though. Here is what I suggest:
http://www.amazon.com/Mixing-Audio-Concepts-Practices-Tools/dp/0240520688
Alright, so now you've bounced your final mix of a few songs. But they seem a little quiet. This is when you will be
mastering- putting those tracks where you want them to be in relation to each other. You will want to apply EQ and compression, here, maybe. You may want to do a lot of things, that's up to you. You can normalize at this point as well, if you want to. This is when you complete the tracks- make it ready for commercial release is the goal, even if you are giving it away. Wave Burner is the Logic Studio software designed to make this easy.
You'll be wanting to do some reading!
http://www.digido.com/vmchk/shopping-cart/mastering-audio-by-bob-katz/flypage.tp l.html
Both of these areas are something that a person can work on for a lifetime. Do your reading. Good luck, L