Hard Edges vs. Soft Edges: Directing the Eye with Visual Hierarchy
Stop trying to tell the viewer everything at once. Use your edges to whisper the details and shout the focal point.
art-fundamentals
Color Relativity: The Physics of Perceived Value
Your final color is simply the intersection of those two things. If you understand the light source, you know how to shift your color. If you understand the local color, you know your starting point. If you ignore either of these, your colors will look disconnected and flat.
Visual Literacy: Shifting from Recognition to Spatial Analysis
Your brain is a recognition machine. Its job is to identify things as fast as possible so you can navigate the world.