Yahoo CEO Marissa Mayer may have slept an opportunity away.

Last Tuesday, Interpublic Group arranged a private dinner for Mayer to meet marketers from top companies including food giant Mondelez International and Greek yogurt company Chobani. The purpose of the gathering was for Interpublic and some of its clients to get a first hand update from Mayer on what Yahoo had to offer them.

But Mayer was nearly two hours late, and several dinner attendees, including IPG Chief Executive Michael Roth, supposedly left before she arrived. Mayer reportedly told some attendees that she had fallen asleep.

We’ve all been late or missed an appointment at one time or another. Crowded schedules and traffic and weather delays are usually the most popular culprits. It can be embarrassing and downright humiliating, especially if the meeting is critical to your company’s success. More importantly, it can sabotage a person’s trust in you.

Related: The 3 Qualities of Likable People

In most societies, being late is inconsiderate while being on time is an expression of respect towards others. It’s also good etiquette.

If you are time-challenged or chronically late for appointments, here are some ways to prevent being late in the future.  

Set your clock 10 minutes ahead. By doing this, you trick yourself into thinking that you have less time to get to an appointment.

Set an alarm. Program the alarm on your phone to remind yourself to be somewhere on time. When traveling, have a back-up plan. Set your alarm clock and ask the front desk for a wake-up call.

Leave early. Leave an extra 15-20 minutes early, just in case you run into unexpected traffic and parking delays. Give yourself time to find your meeting location, go to the restroom to check your appearance, and gain your composure.

Related: How to Receive a Compliment Without Being Awkward About It

Reward yourself. If you arrive early, bring a good book to read, relax and have a cup of coffee, or check emails until the other party arrives.

Don’t overcrowd your schedule. If you’re a person who finds it hard to say no, you may be juggling too much, causing you to get stressed and lose track of time. On days when you have important meetings, schedule some time in between tasks and meetings. This time acts as a buffer you can borrow from in the event you’re running late.

Beware of time suckers. Technology, chatty co-workers and last-minute requests can eat up your valuable time if you’re not careful. When you think you can respond to just one more email, stop yourself, turn off your computer or smartphone and get ready for your next appointment.

Give yourself positive reinforcement. Give yourself a pep talk and stop defining yourself as a late person. Instead, say something like, “I am a punctual person,” or “I am always on time to meetings.”

Related: 6 Secret Weapons of Shy Entrepreneurs

If you accidentally run late or miss an appointment, due to unforeseen circumstances or otherwise, the burden is on you to apologize and do whatever is necessary to save face. Here are some tips to recover when you miss an appointment.

Call ahead. As soon as you suspect that you are running late, give your clients or colleagues a courtesy call and let them know right away so they can adjust their schedules accordingly.

Apologize immediately. If you accidentally miss an appointment, call the person you are supposed to meet and apologize. Better yet, write a note of apology. For example, the note or email might read, “Please forgive me for missing our appointment. I value your time and realize you made an effort to meet me, only to be disappointed. I apologize and would like to make it up to you. May I treat you to dinner next week? Again, please forgive my temporary absent-mindedness.”

Don’t over apologize. Everyone makes mistakes. Apologize once or twice and then move on. It’s best not to belabor the point when the person has forgiven you.

Related: 6 Types of People Who Are Really Hard to Talk To

Be honest. Honesty is the best policy. Don’t make lame excuses or play the “blame game.” For example, if your last appointment ran late, say so and apologize for not letting the person know sooner.

Reschedule the meeting. If you’re the one who missed the appointment, reschedule when it’s most convenient for the person whom you inconvenienced.

Be there early. When you show up for the rescheduled appointment, be there early. You can’t change what happened in the past, but you can control manage your schedule in the future.

Related: 5 Ways to Be a Better Listener