The main difficulty in engineering and mixing audio is simply
no two cases are alike
Someone will give you advice on compressing say a bass using this and that with that kind of ration and this kind of Release,
although that can be helpfull it won't get you to much closer to your goal as no 2 cases are alike. U might use a different bass with a different player (feel has a lot to do with compression etc...) different pickups, Amped versus direct, different pres..etc..etc... Every song demands a different direction of compression on the bass, depending on feel, tempo, concept and more....You get the picture.
I think you need to understand (but really understand !) what each knob on your (for example) compressor does as in before you move it you can basicly guess what sound your going to hear.
What do you hear in your head and how do you twiddle the knobs to get that sound you hear in you head.
If your still guessing then your still going to have trouble getting a really good mix unless you get lucky.
I would suggest you break it down to the basics of mixing a drum kit with bass and vocals. Work your way up from mixing the kit with compression/gating/Eq
ONLY No reverb, no fancy shit,
Work on proper use of the gate first understand the parameters,
compare before and after...ask yourself is it better? why?
Check the kit after gating and if recorded properly then it should already sound good even that RAW. Use some EQ by finding offending freq's. Dont look to improve the sound with fancy EQ. Look to remove problematic freq's. Again listen to the kit. If recorded properly then it should sound good ! RAW !.
Add the bass - how does it work with the kick?. Don't rush to EQ the classic "boost kick here/cut bass same place....." Just listen for - problematic masking and try to cut the bass a drop on offending freq's if they exsist (if not then your half way there).
Are they working together well? do you have enough ooomphhh and support as well? are they grooving well together? (if not ...then get the musicians back to rerecord....hopefully you got it to groove during the recording process).
There is a lot more I cant simply write a text book here
but the idea is basic simple but extremly effective (not CREATIVE!!!-
Effective) EFFECTIVE moves. Make every move count !!
And be patient !!! like every thing in life its experience...work..and even more work.....A lot of mixers can get a good mix going.
What seperates them from the top ones is the creative mix's done with talent.
Don't aspire to be so creative now but remember the key word - EFFECTIVE. You'll have loads of time to be creative later. but if you cant work a compressor with out helping the sound ( or even worse degrade it) then your far from closing in on a mix you hear on your favorite cd.