^^^ some real good advice! 
Like tom said - give your ears a break from the track for a few days and then go back to it with fresh ears.
You'll then notice the finer details that need work, rather than getting frustrated with the whole thing and not knowing where to start...
Go through the tune track by track (solo-ing perc together, bass and kick, leads together etc) find whats clashing in certain frequency ranges and either adjust EQ or adjust levels to suit.
Try not to have to many sounds in the same frequency range (especially low-mids and lows) coz it will start to sound muddy with too many layers. Also as mentioned, try panning some of your perc sounds and loops to give the track some breathing space.
Once your mixdown sounds right, try a multiband compressor / limiter on master channel - (PSP vintage warmer, Waves L1, L2, L3 ultramaximizer etc etc) play round with as many as you can, but dont over-do it like i always tend to do haha!
It just takes time dude, and you gotta be patient and constantly play around / learn.
God knows i have pulled my fucking hair with some tracks and thrown my toys a few times 
(i havent listened to your track yet so dunno whats going on but will do..) 