The colors you see in Unity don't match the colors you see in the Game. Below are two images from a rough course using stock textures. The first is taken in Unity's Scene view, the second is in Unity's Game view:
As you can see, in Game view, colors of textures, trees and sky are brighter and washed out.
When actually playing the game, adjusting the various Graphics Settings sliders does not help.
Most of the wonderful courses from experienced designers that I download and play have little or none of the washed out effect found in my image/course.
Here's my (very broad) question: How do you folks deal with color differences between Unity and the Game?