Here's how I would do it:
What set does my animation require?
A street.
Okay, so how many buildings should I put on the street?
Let's say two.
What colors should they be?
One white and the other light grey.
Builds.
I got windows, doors. Something's missing...
Details!
Raise the white building up a bit, add some stairs and windows to that.
Windowsills, outdoor lights, canopy over the door, ect.
Benches, streetlights, fire hydrant, on the sidewalk.
The trick with details is:
1: Experiment with different pieces to make something
2: Just enough details to look pleasing, yet not distract from the charaters.
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