Today’s prototyping tools and software are so advanced that you may get carried away. It’s not a good idea to spend too much time on the first design you come up with. The reason is that it can cause frustration, and can make you slow down later on. To prevent over-prototyping, you may want to concentrate on the work and get the task completed in the fewest steps possible.
Another common mistake is to make prototypes without performing a reevaluation of the fidelity. For instance, you may want to sketch on paper to collect customer feedback instead of making a highly interactive prototype. You should consider your desired goal to settle on the best fidelity for your final prototype. Since the role of prototypes is to test assumptions, keep in mind that not all of your assumptions will achieve validation. However, you may not want to take it as a failure. You should reconsider your definition of failure and success. Every failure will teach you a great lesson.