Shackrock,
You're kind of like the guy who's been skipping class, but then shows up the day before the test and copies everyone else's notes.

Just kidding with ya, Shack.
Now I'm sure this is a phenomenon you can relate to Shack: Have you ever had a hard time hearing a particular instrument/track in a mix . . . yet you look at it's volume and it appears to be plenty loud enough. What's going on? Well, what's likely happening is you have other instruments / tracks that are covering it up. And by covering it up, I don't mean that they're too loud. What's probably happening is that it's using a lot of the same frequencies.
So your solution is NOT to increase the volume of the track you can't hear. It's already loud enough. And similarly, you don't necessarily want to decrease the volume of the instrument that's interfering, because then you might have trouble hearing THAT track.
The idea is to change the eq on one or both tracks so as to "reveal" the sound of the track that's kind of buried underneath all the mud created by the track that's covering it up.
If you go back to the first page, one of my first posts dealt with some of the uses of the spectrum analyzer. Particularly using it to give greater definition to the kick and bass guitar tracks. I'll give you an ultra-simplified version here anyway, just in case:
When you view individual tracks through the spectrum analyzer, you're getting a look, graphically, at what frequencies it's pumping out (There should be some numbers displayed somewhere, usually at the bottom). If you know what frequencies something occupies, you can apply that knowlege when "carving" frequencies out for other tracks.
* Watch on the spectral analyzer and note the main frequencies the kick drum is using. Again, there should be numbers somewhere that indicate this (usually it's around 60-80 hz).
* Do the same now to your bass guitar tracks. Are the bass tracks pretty strong (are you seeing a lot of peaks or lights) around the same region as the kick drum? If so, then you probably have some conflicts. Both instruments are competing for that same frequency range, and it could be turning in to a big mud fest down there.
In this instance, you should pull out whatever EQ you have available, and start cutting some of that region out of your bass guitar track. This will give your kick some extra breathing room, so you'll be able to hear it better in the mix. Otherwise, what often happens is you will find yourself turning the kick drum up way too loud in order to hear it better in the mix. This will result in the need to over-compress during mixdown in order to tame all the action and/or peaks going on around it's frequency range.
In reality, all you needed to do was give your kick drum some of it's own space. It's kind of like Marriage in a way.
Jigsaw Puzzles:
If you have the ability to view the peaks on your spectrum analyzer (Brainspawn has a "hold" function), then take note of the "shape" a given instrument has. Draw it's shape, if you can. Where are it's hills, valleys and peaks?
Now, Ideally, you should be able to invert the shape of the kick and snare drums, and fit it in to the bass guitar track as if it were a jigsaw puzzle. In other words, there should be a couple of valleys in the bass guitar track around 80 hz and/or 200 hz.
Similarly, there should be peaks/hills in the drum tracks in those same regions. See? Jigsaw puzzle. And the 80 / 200 thing is just an example. Yours might be closer to 65 and 225, which is perfectly fine. Just be sure that you have some room in your bass guitar track in those regions for the kick and snare to sit in.
That's a good place to start with it all . . . and it's also a good place for me to finish the rest of my Busch and get to bed.