Keep a calendar and follow it. Keeping a calendar helps you stay on-task and it helps you remember what you're supposed to do and when you're supposed to do it. Committing to something or meeting with someone and following through helps you be a person of your word and helps to buiild trust.
On the other hand, if you have an appointment or something to do that you don't put on your calendar and you miss an appointment or deadline, then you come across disrespectful and selfish because you're wasting other people's time. Others then view you as not being a person of your word, because you didn't do what you said you would do. If you are a top producing employee, but don't follow up or follow through you may end up doing more damage to the company than good. Be a person of your word. It's one more way to model the way by being a person of integrity by doing what you commit you will do.