I'm pretty new to this (2 weeks in) but I've a couple of tips that may help:
Your light is too harsh, bounce it off the walls or white card, I've found if I can see hard shadows and sharp hilights it's not going to happen.
More varied angles in your photos, do at least a low, mid and high pass of your turntable and get in closer to your subject.
I've seen online, though not tried it myself, that sprinkling the subject with talcum powder or just painting it matt will help. Of course you are sacrificing the texture capture doing this but it's quite a simple colour job anyway.