It is especially useful if you want to use some specific statistics to make the sections of your wheel (population, for example) I have made an example of a Trick or Treat wheel on that website which would be used on your front doorstep 'Trick or Treaters' would spin the wheel and depending on whether they got a trick or a treat, they would be given a candy or sprayed with silly string (or something similar and non-harmful). *You can use this website to create a mock-up of what your wheel will look like:

Mark each section with a certain prize or number.

Allow each segment to dry before you start a new one. Then, apply spray paint or apply paint with a brush. It is easier to fix mistakes on the plywood so make all of your initial marks directly on it and then, once you are sure, go over them with the permanent marker.