Underestimating

When you knock yourself out doing a job that takes way more time and effort than you ever dreamed it would, try to think about what you learned from this mistake. Of course, the key is to apply those lessons the next time you think you know how long a project will take. Chances are this is not the first time you underestimated; and, unless you figure out why you fall into the same trap over and over again, it won't be the last.

Ask yourself a few questions: Are you estimating from experience or off the top of your head? Have you ever done a project like this, or are you in uncharted territory? Do you have a tendency to make everything more complicated than it needs to be? Have you accurately assessed your client? Are you a perfectionist?

It pays—literally—to know the answers.