When an artist is having trouble with their work they often think it’s because they are choosing the wrong colors. If they just knew the right magical combination of colors every problem they are having would be solved! More often than not, color is not the issue. It’s values, contrast, and the accuracy (or lack thereof) of their drawing. Sure color is important…but not THAT important if you have the other points taken care of.
When I see someone’s work that looks flat it isn’t because of their color choice. It’s because their values are mid-range, or “safe”. Having your dark areas really dark and your light areas really light is scary! I get it! But when those dark darks and light lights are missing, the work looks flat no matter how well it’s drawn. Learn to create depth and dimension with your values instead of trying to do it with your colors. This will make all the difference in the world in your work!! I recommend everyone spend extra time working in black and white to really master your skills in rendering depth with just the two tones. Then when you switch to color, as long as you have the right values and contrast, your work will have that dimension you were missing before!