"I went through a lot of trial and error for 40 years," says McEntire
The 50th Annual CMA Awards - Arrivals

Reba McEntire has learned a lot over her years in Hollywood and the country music world, but the best advice she ever received was from her mom, Jacqueline.

“Mama always told me, ‘Reba, it will be over in 24 hours. You can go stand on your head for 24 hours,'” the “Going Out Like That” singer, 61, tells PEOPLE. “That’s really helped me to be my best self because I just focus on the task in front of me and I don’t get overwhelmed about everything else. Don’t stress so much over what happens tomorrow. Live today.”

Now the legendary recording artist is passing on some of her wisdom to a new generation of performers through her new MasterClass, an online course developed to teach the ins and outs of performing and navigating the country music industry.

“I went through a lot of trial and error for 40 years and now I’ve gotten to a place where I feel completely comfortable with where I am and what I’m doing,” says McEntire, who split from husband Narvel Blackstock in 2015.

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As for the most important lessons she could teach, she says it’s simple: be a good and considerate person.

“Singers have to treat their bodies like it’s their business. You can go out and party the night before a concert, but remember that people paid good money and got a babysitter to come see you perform. If you’re tired or your throat is sore from yelling at the bar, you’re not going to give them the show they deserve,” she says.

“I’ve seen people phone it in before and it aggravates me so much. Be prepared and treat people like you would want to be treated. That’s not just in music. That’s a lesson for life.”

Reba McEntire’s MasterClass is now available at masterclass.com.