I keep seeing this nail trend and would love to give it a try but it seems more doable on short nails. I first saw it on Sivan Ayla and thought how cute. Then Stylecaster posted a pic of these Autumn color inspired tones too. I lean more towards the pinky tones but love how it looks overall.
To get it right, I think it is important to consider the undertone. It should be either cool or warm. Then stay in a color family that moves from light to dark. A trick that I think might work is to check out paint swatch color palettes and pick polish colors to match. Design Seed is a cool site to look at, they put color palette ideas together for you.