This has to be the worst garage band mix I have ever heard. First for the intro since I use garage band add some of the other synths under it trust me they sound really good mixed together then the low pitch to high after the first synth no no
OK I WILL HELP YOU
a) add reverb
b} keep in time, make sure instruments come in on the beat or in the middle of the beat unless it is jazz. I say this because when the second instrument comes in at 16 it doesnt sound right.
c) add snare and hi hats, it does so much beleive me.