Mistakes people most often make when preparing a to-do-list

Have your working day planned and prepare a to-do list: this tip is the one most often mentioned in terms of how to be productive and organise your time well. But writing a to-do list is a more complicated matter than it may seem. Many people make mistakes in this apparently simple activity and thus fall far short of using the potential of a to-do list to its maximum. What are the most common mistakes and why should you avoid them?