I love Howie Post's backgrounds. They are caricatures of the general Harvey house style. You notice right away how interesting the details are-the shapes of the trees, the creative bark textures, the clever and stylish shapes of the leaves.
But details don't make a good picture!
LARGE NEGATIVE SHAPES
He doesn't fill a whole tree evenly with bark textures. Note that some areas have bark details close together - but these clumps of texture are separated by other clumps with ample spaces in between.The characters are always clearly framed by the bgs and the negative spaces between the characters.
The empty spaces are just as pleasingly designed as the positive shapes of the characters and objects.
All the details are small and in organic (non-mathematical) proportions. That's so the details don't draw your attention away from the much larger forms that they wrap around.
He has an infinite amount of ways to draw leaves, without having to draw each individual leaf.
Sometimes his foliage looks like it's from another planet.
Post uses hierarchy of forms and spaces beautifully. All those girls running towards Hot Stuff fit within a flowing organic shape. Plus, they are not evenly spaced. That makes it appear natural, even though Howie is completely controlling the image.
Again, besides marvelling at the beautiful cartoony tree, look at how much negative space there is - both:
1) Surrounding the tree
2) Within the details of the tree. (Nate!)
Each layer of sub forms describes a clear and distinct form, which is in turn subject to the larger form it wraps around.