Regardless of the color you choose to be the focal point of your tree, you want to stick with that color and not veer too far off. This is called the "base color" (via The Spruce). The color you choose is totally up to you; however, you may want to select one that compliments the colors of your home and other holiday décor.
Collecting your ornaments, balls, trinkets, and lights in different hued variations of your base color is essential in following the monochromatic vibe. You may also want to add neutral-colored ornaments, like white or silver, to compliment the base color and "round out" the tree (via An Indigo Day). But again, don't step too far out of the box in a completely different color scheme.
Also, just because you are sticking with a single color doesn't mean you have to stick with a single shape! To add extra dimension and character to your tree, don't be afraid to hang different ornaments in various styles and sizes (via Martha Stewart). Go through your Christmas ornament collection and pull out any decorations that fit the color theme — regardless of shape — and use them to add texture and playfulness. A stroll through your local thrift shop may also provide fun and whimsical single ornaments of your base color.
