Yeah, sure.
Well basically what I do is, I have an idea in my head, then I put it on PS the best way possible, ya know turning my thoughts into reality. If you're a beginner, start basic ya know, don't try and do all the effects and what not you see on other covers, do you, you may even start a style other cats will try and copy, feel me?
Oh yeah and try and follow some tutorials, e.g. make stuff on photoshop from
Web Templates and Flash Templates, now you might think what the fuck dis gotta do with covers, well, following these tutorials will aid your knowledge in PS, you'll get to know your way around the software alot quicker than before, and b4 you know it, you'll see those covers and think hey, that's pretty simple, all you gotta do is... get me??
I hope this helps!