Reliability is an imperative element of a professional image.
If you say you are going to get back to someone with an answer before the end of the business day, do you?
Do you meet deadlines or does your supervisor have to track you down?
Are you on time for meetings?
If you are going to be late do you call to inform the people waiting on you?
Did you complete the task you volunteered for during the last staff meeting? On time?
If you answered no to any of these questions, you need to work on your reliability skills before your next review for a promotion. If you don’t, you shouldn’t be surprised your co-worker is promoted before you are.