60-30-10 rule may help you harmonize your color scheme and make a well-balanced interface design.
The idea is simple —when you choose a new color palette, the 60% of the palette should be dedicated to the dominant color (usually, it's called neutral), secondary color (that is considered as complementary) makes up 30% of the palette, and a third color (accent) is used for the remaining 10% of the design.
This principle came from interior design, where it is usually applied for house decorating. The beauty of being a designer here is that sometimes you don’t need to stick to one area as UI/UX, and can implement useful rules from another as interior design, to enhance your project.
The 60-30-10 rule may become a solution for balancing the visual experience and is surely easy to apply.