It doesn't sound too bad to me - I've heard much worse!

Basically, you've got to give each instrument its frequency space to live in. Generally speaking, that involves reducing the amplitude of those frequencies in the other instruments. It's a bit hard to do that properly when you're dealing with samples played at different frequencies, though. :/
Moving to higher bitrate samples might help a little, too, if that's possible.
Nice little track, btw.

But that low sine in the final pattern kinda messes with my ears. :/