The tone on tone trend is simply a stylish and classic minimalism if done properly. That is, certain things have to be put into consideration before pairing color hues, and these little but very essential details are: fabrics, color hues, body type and skin tone. The tone on tone style is different from doing a monochrome, it’s about picking the right hues of a color family, the right fabric or texture combination and putting them together without looking like a single color masquerade or like you tried too hard.
The trend can instantly transcend ones look and exude refreshing, relaxing and bold aesthetic if styled the right way. The key point is to mix textures and shapes/patterns in proper layers , and pick hues that sit well well with your skin tone.
In respect to body shapes, my candid advice ; for people with wider /fuller upper body, or you are looking to shift attention from your upper body, you should wear darker hues of the chosen tone on the lower part of your body (that is, waist down ) . Secondly, lighter fabric texture should be worn on the part of the body where you want to appear slimmer or smaller.
Finally, when doing a tone on tone, accessories should be very minimal and within the same color family. Go for nude, black, brown, animal print or metallic shoes. For makeup, nudes are timeless , simple and safer , but if you are wearing a bold color like red or burgundy , match your lipstick with the darker hue in your outfit for that edgy look.