A patent application needs to describe an invention and ensure the patent is 1. Novel, 2. useful, and 3. non-obvious. Patent law requires that a patent application explains the invention to someone who is not already familiar with the invention. One way to easily do that is to assume that you are explaining the invention to a non-technical person and even a child, but ensure that you stay focused on the main criteria of patentability (novelty, usefulness and non-obviousness)