Using real life photos for ideas of your next Minecraft GFX artwork is very helpful. For example, look at the image below...
In this image the character in the foreground is out of focus while the landscape is the main focus, a similar artwork could easily be replicated in Minecraft GFX, using just a Minecraft screenshot and a Minecraft render.
For the screenshot, I might use something like this:
Or this...
After I chose a screenshot, I would make the appropriate edits with the sky, colors and renders.
Just like that, you can find real life images, get inspiration and ideas, and even build off of those ideas!