Alright, first things first, a cover is in no shape or form related to a sig.
With that said, you should not treat designing a cover, like designing a sig. That first cover up top looks nothing like something I would see on a CD, it just looks like a square sized sig I would see on RV.
You need to draw attention to the title and the artist. In the second cover I cant even read the artst name (not good). Try and refrain from the whole, blending the text into the background thing, because thats going to make the text harder to read. Its a cool effect for sigs, but rarely looks good on covers (unless you do it right).
Try and match the photos up when it comes to brightness and contrast. If you can at least do that, you should be ok, but if you want to get it to look even better try and work with the shadows and highlights.

Try some of that out, and see what you get.
But remember, do not treat a cover like its a sig.

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