A lot of my art teachers say that if you are to do studies - you should only do old masters like "Sargent, Rembrant" etc... and avoid doing copies of other concept artists. I think that is absolutely ridiculous! That's like a football coach telling his football players to practice swimming to get good at football. There may be some supplemental benefits - but overall it doesn't really make sense. C'mon. 
So here I wanted to practice doing a birdseye view. So I took the original image, put a gaussian blur on it, and repainted the image on top of the original while color picking and toggling the layers on/off. It took me 9 hours. Good workout. Without this photoshop technique - it probably would've taken me 2-3 times as long!
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| done. this was a Fox theme park - dunno which one. | 
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| Chris Turner study 1.5 hrs - love this guy's work. | 
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| another study - not sure who this is... 2 hrs | 
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| Joey Chou Study - 3 hrs | 
And after the studies, what I do is another piece is similar in style and subject to the original master copy. Just to synthesis the information and see what I learned...
"Swamp Town" - 30 minutes. inspired by Joey Chou style.
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| red moon spaceship - spit paint |