Please don't take this the wrong way (people always take this the wrong way

).
In your first post, you mentioned that you have "figured out how to do pretty good in mastering" then in a later post, you don't understand what the relationship between peak and RMS levels are. It's likely that you have a tremendous amount to learn about recording and mixing - Not even going into mastering.
It's a lot more than slamming something through a limiter or compressing a track to death to make it loud. The subtleties of ALL the steps from start to finish are MUCH more important than the obviosities. And the subtleties require a certain amount of experience to achieve.
Again - I'm totally into doing the best you can with what you've got, but it seems that every other day, someone posts about why they can't make a recording with almost no experience and $2000 in gear sound as good as "pro" recordings made in multi-million dollar facilities and crews of people with decades of practical experience at the craft.
The opposite is also true - There are plenty of bands out there with more dollars than sense that go TO the multi-million dollar studios and they STILL sound less than stellar. Their own sounds are their own worst enemies. I used to have bands show up with dented drum heads, two-year-old bass strings, vocalists who droned through their nose, horrible sounding guitar multi-effects units - the works. When everything was done, they wondered why they didn't sound like Metallica.
It's just not realistic...
The point is that everything - EVERYTHING - in a recording from the start has to be "up to specs" if the final result is to be. The talent, the room, the engineer, the gear, the song, the mix, the mastering... Everything has to fall together in a way that benefits the whole.
Quality gear is important - however, with a good performance and an experienced engineer, the quality of the gear is much less important - Blue Bear has a quote in his signature that goes something like
"George Massenburg can make better recordings through a PortaStudio than a monkey with a Neve" or something similar.
It doesn't get any more true than that.
SO - Do some experimenting - Read some books - Record everything you can in every way you can, from every angle, with every mic, and listen to what they're doing. I'm not saying to get a degree - Just some basic need-to-know type stuff. Soak it up like a sponge. Learn the rules, and break them all.
And for God's sake, keep the levels reasonable. Almost everything out there is smashed - I can accept that. HOWEVER, if it's going to be smashed, smash it ONCE during mastering. Not on the input, then the mix, then the "half-asster-master" - One time. The last thing that's done. Worry about getting a good mix of a good tune. The volume will come if the potential is there.