When it comes to hair, generally there are 4 different types - Type 1 being straight hair, with each individual strand becoming wavier or curlier as you go down the list. There aren't too many examples of 3D NPR hairstyles below Type 2, which makes it hard to find references to make your own. However, you can create a similar basis with curve hair.
First, start by adding in a bezier curve and a circle to go along with it. It is highly recommended you use "Path" over the normal "Bezier" curve, as Path is more flexible and allows for better control over your strands.
As for the bevel circle, it can be whatever shape you want. For this example, the shape is a trapezoid. Set up the Path hair strands to fit your character to your liking, then select the bevel circle shape and go into edit mode. From there, select two points and duplicate them with Shift+D, and move it away from the main shape.
You can add as many of these strands as you want - they will behave like the bigger strand in terms of twisting and bending, and can be scaled and/or rotated separate to the main shape. They also allow for interesting shading effects when paired with a basic toon shader. Rotating the strands at certain angles like shown above will allow the smaller strands to contrast the main one.