Have you done something wrong and need to apologize? Whether an apology is in the professional setting or a personal setting, sincerity and brevity are keys to delivering your apology.
Keep your apology brief – state the infraction and express your deep regret. You can add any policy or personal changes that you are going to implement to keep from repeating the infraction, but never make excuses or blame others. Just apologize. Period.
Sincerity is important in an apology – but the way people receive your apology is based on established trust (or lack thereof). So the believability of your apology is judged over time. If you are apologizing for a repeated behavior in the past, is there any evidence that your pattern has changed? If not, then people won’t believe that you are sincere in your apology. And if future actions repeat the infraction you apologized for, then people will assume your only regret was in getting caught, not in the actual action.
Keep brevity in mind, especially when giving a verbal apology. Just because someone gives you a microphone and 2 minutes, there is no need to keep going on and on. State your infraction, express your regret, and lay out your plan for moving forward.
Note: An apology for a mistake is different from a disagreement over opinions. See a previous post for responding to feedback.