Talking about layers, you can apply layers on some hairstyles. For long hair for instance, you can apply layers gradually, specially if your hair is curly or straight. The layers can be started from near the ears until the bottom of the hair in below. Let the layers gradually from up to bottom with the deep and slight layers by the special scissors for hair layering. But if you want to make it to be short layers then you can try to give the layers from your shoulder. That would help you to make the layers on long curly and straight hair perfectly.
But if you don't want to be in long hair, medium and short would be okay too. In some short hair with layers case, the layers started from near the bangs. Bangs, with or without it would look good since the blunt bangs make perfect frame, helping the layers to make super good framing for face. What about in curly hair? Layers can be done at short curly hair too, yet the layers wont be as clear as in the long straight or medium straight hair.
Image source: woohair.com