Well one thing I can tell you for sure is that it takes years and years of practice, a balanced room, and some great equipment. First thing you should do is read then read some more and oh yeah read even more.
Every step - the arrangement, the talent, the core sounds of the instruments - All of that has to be in place from the start for the mastering to mean anything.
Now if by "industry CD's" you mean "loud" - That's not too hard with the right gear and the right ears. It might not sound good, but with a lot of people, sheer volume is all that matters (which is really, really sad).
Someone could say somthing like this.... "Try a program called T-Racks Mastering Tools, Its not going to sould mainstream, but then again i doubt your mainstream. its a decent tool for newbs."
If you're just looking to get your recording level up, you're looking for a limiter. Basically, it'll increase the average volume while "levelling" the peaks so you don't clip the signal. A compressor with a high ratio is a limiter.
T-Racks is a really decent program for $300. For about $1000, you can get the UAD-1 card with a few of their mastering tools.
I have wavelab and all the waves gold bundle plugins, but I am too stupid to use them properly. I can NEVER get the volume up properly (not talking super loud, but having to turn up my volume several notches to listen to my stuff is annoying). So I use T-Racks. It can sound decent if you play with it a bit.