How do I get Fruity Loops tracks to sound good in iTunes?

I know... I use Fruity Loops. It's easy; I'm not a professional or anything, I just want some cuts to throw in my mixes. And I kind of want to rattle the windows with my own beats sometimes.

Anyway- seems like no matter what I do, the .wav files sound awful. Like they're playing on cracked speakers. Any idea what I've missed? Like I said, I'm pretty much just a casual non-musician, and it wouldn't surprise me to learn I missed a common-sense step (or two).

Thanks.