The example you present is rather awesome, what about on the more “vector” side of examples though?
I’m not a psd layer guy, not something I want to do.
Wow that’s a tough one! There are so many!
I guess it depends the category you are aiming for – flyers, graphics etc are pretty high quality a detailed whereas the likes of vectors are not so much graphically amazing but are pixel perfect and tight in design.
The bottom line is attention to detail and refinement.
Slightly off topic we just bought this: http://graphicriver.net/item/wild-night-flyer-template/5196689 its incredibly detailed and amazing use of shadows etc.