Tim--I agree--never give up on this. You can get it--anybody can if they put the time into it. You shoulda heard my first stuff! ChrisHarris has gone up several notches since he came here too. So have a lot of others who are now blowing me away with their work. You are gonna get better and better at this.
I have a feeling that I know what your problem is--you have too much information and it's confused you. Happens to me all the time! Let's break this down to basics, using your posted tune , Mustang Sally.
Before we even think about EQ or effects, lets listen to the raw sound sources and think about the arrangement. At the foundation of the song, we have bass and drums. The first key thing is to get the bass and the kick drum working sympathetically with each other. When they are, they create a pulse that is more than the the two separate parts. On your mix, the bass is drowning out the kick. Change the levels of both until they hit the sweet spot. For lack of a better example, listen to some Fleetwood Mac tunes. They were masters at getting this part right.
Moving on to the snare, your snare is lacking in all midrange components, like it was EQ'ed out. It doesn't sound like a real drum anymore. Try using no EQ first, and a general rule is that the snare is as loud or louder than the kick.
Your hi hat is the loudest drum by far. It needs to come back to the point where you hear/feel it keeping time, but not any more than that. Imagine playing with the drummer in your band as if you were standing by him and ry and mix the kit like you would hear it live.
Once you get the drums/bass grooving, I would do two things that you didn't do here. First, I'd add a rhythm electric guitar. Fairly clean, panned to 2 or 3 o'clock, say left. I'd also add a keyboard-either piano, electric piano or organ--panned 2 or 3 o'clock opposite side. Niether of these have to be real dominant--they are just reinforcing the groove. Most ensembles are bass/drums/keys and rhythm guitar. If you can get that working, you'll just be filling spots with guitar fills and horns, etc.
Anyway, once you have all the parts, try to mix everything so you hear what is going on on all the instruments before you start EQing anything. Get the mix as good as you can get it with no EQ. AT that point, walk away for an hour.
Come back, and listen to the balance of the frequencies. Is there a big lump of low end? Figure out whats causing it, and EQ the selected area until that cardboard-sh sound goes away. Is there anything that pierces your ear? Its midrange. Figure out whats doing the damage and tweak that with cuts until it sounds natural without the spike.
Now, for the hi end, go back and forth between a CD you like and your mix until you get a similar degree of hi end in your song.
Now, go back and listen for each instrument and drum kit part and see if its all there. If something has disappeared, try bringing it up a bit with straight volume before you try and EQ it into existence. Consider EQ as fine tuning, not as the key component of a mix. The most important things are always the recorded source and the relative levels and pans. EQ is added after you have all that working.
Then, if you want, play with the reverbs and echoes, etc. Consider those spice also--a little goes a long way. (Listen to me! Mr. Reverb Over-user!
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Try and see what you come up with.