I sat down on my couch, switched my phone to selfie mode, and hit record. Then I started answering the dreaded interview question: “Tell me about yourself.”

After what felt like the most awkward four minutes of all time, I played back the recording. It was painful to watch. My body was stiff and my eyes darted all over the place. I clenched up in some parts, and rambled on in others. I said “like” about 4 billion times. Tell me I don’t really sound like that, I pleaded to an audience of zero in my empty living room.

In my head, I cursed my business coach for recommending this exercise after I’d mentioned I was nervous about possible upcoming job interviews. I’d always been anxious when it came to speaking with new people — as a kid, I grew up with a severe speech impediment. My coach had suggested that I record myself answering common interview questions every day, and see what happens. After that first sweaty episode, I wondered if there was another way to improve my speaking skills — one that didn’t involve having to stare straight at my mug, growing increasingly uncomfortable while watching myself be uncomfortable (it was all very meta). It turned out that sure, there are tons of ways to become a better speaker, but this one allows you to see immediate improvement, make changes as you go, and best of all, you can do it at home behind closed doors. I decided to stay with it.

The second time I mustered up the courage to hit record, something happened: I was less terrible. Not great by any standards, but my response began to resemble an answer rather than a jumble of words. Then I did it again the next day. And the next. After about a week or so, I noticed that I was able to maintain eye contact in the right moments, keep my responses to the point, and even look like I was having a real conversation. After two weeks, I stopped feeling so self-conscious and started showing glimmers of confidence. By week four, I was having fun.

Years later, I must say that keeping with this tiny exercise has shaped my career more than any other. Yes, I received job offers, but beyond that, I was promoted to management in my first year in sales, and when I moved to Spain, I became a communication coach and have been invited to teach presentation skills to politicians and business leaders.

Try it for yourself. If you want to improve your interview skills, print a list of the most common interview questions in your sector, then grab your phone, hit record, and start talking. Whatever you do, don’t stop recording until your answer is finished. Learning how to recover well is just as important as learning how to respond well. If you simply want to improve your speaking skills, you might try talking about the high and low of your day — or any other topic.

Give yourself a 30-day challenge. As you watch your recordings, look for areas where your body language, facial gestures, and tone can improve. Find spots in your responses where you can slow down or pause in order to drive a point home. The difference between the first take and your 20th will astound you.

Throughout your career, your interests will change and jobs will come and go. But strong communication skills will always be critical. So hit record and allow yourself to be terrible. It won’t be long until you’re not.