Another common mistake beginner artists make is choosing all very saturated colors or picking colors with the same tone. This leads to images that can strain the eyes or colors that all blend into one another. Varying intensity and value in color choices will keep the image cohesive while avoiding dull or ugly color combinations.
A fast and easy way to check if your values have enough contrast is to place a layer of pure black over your artwork and set its blend mode to Saturation. Removing all the hue from your artwork will let you see how your colors interact.
The image above uses all the same Hues, but the intensity and values of each have been adjusted to create greater visual contrast.
Conclusion
There is a whole world of color that often intimidates beginner artists. Even accomplished artists who have been in their field for years have yet to learn everything there is to know about this exciting topic of study. The good news is that you don't have to be an expert in color theory to be able to make fantastic art.
Understanding the basics of how colors work together and how to use them in an image is all you need to craft engaging designs. Using variations in saturation, value, and blend modes can make even a palette limited to two colors yield beautiful results.