I usually mix with everything peaking at no more than -8db, but generally TRY to keep my mixes between -16 to -18db while mixing. You make up for the volume/loudness during the mastering stage. Mixing with everything at 0db guarantees you will encounter clipping trying to boost loudness when mastering.
You might want to download something like Voxengo Span, it's a free spectrum analyzer that will let you see what levels you're peaking at and where clipping might be happening. Just do a google search for it. I usually use it on each track individually to visually help me EQ, and keep an eye on levels after I compress, clip and limit. It can help you see peak buildups that may be causing clipping in your guitars, or bass, or drums etc. Sometimes seeing such spikes can help you tame the clipping by some creative or subtle EQing. And then I use it on the master track the same way. On your master track is where you will do some final EQ'ing, and compression, and THEN you will do the limiting and clipping for loudness.
Obviously there are many more complexities than that, but for a beginner, it's a good starting point. Do some searching here on the forums, there are lots of threads discussing this that are plenty helpful. Good luck.
Edit: Do you have bass guitar in your mixes? You mentioned guitars and drums, but no bass. Bass helps give your mix a fullness -- without it, your mix will sound thin and weak, and you are more likely to overcompensate with loudness, when that's not necessary. If you don't have a bass guitar, just record a clean guitar signal and pitch shift it down an octave and play around with the EQ to help give it more bass characteristics (well, as much as possible anyways lol). It won't sound great, but hey, it's better than no bass at all.
thanks a ton.
