Kevin O'Leary is never shy about handing out advice. From his appearances on TV shows like CNBC's "Money Court" to his popular social media accounts, the entrepreneur always has wisdom to share.

O'Leary spoke to CNBC Make It numerous times over the course of the year on topics ranging from investing in dogecoin to shopping for a watch.

As 2021 winds to a close, here are four of the entrepreneur's best pieces of advice to take into the new year.

1. Take care of yourself

At 67, O'Leary is still as busy as ever with TV appearances on shows like "Money Court" and ABC's "Shark Tank," as well as serving as chairman of O'Shares ETFs.

To help stave off burnout, which he said slows his ability to make decisions and makes it hard to "focus on anything," O'Leary said the best thing to do is take care of your body. He recommended getting in some type of movement for at least half an hour each day.

"Pick whatever that's going to be — walking outside, riding a bicycle, running on a treadmill," he said. "Some form of distraction so that you can do something other than work. Your body wants to exercise and it needs to do that, and it has to be something that's done on a routine basis."

On top of regular exercise, O'Leary said it's important to make sure you eat healthy and avoid junk food. When you're overworked or feeling stressed, it can be tempting to turn to unhealthy food to cope.

"The tendency to eat crap when you're working 18 to 20 hours a day is very, very high," he said. "If you really want to be top performing and not get caught up in burnout, food is the most important factor."

2. If you're dating someone new, don't wait to bring up money

If you ask O'Leary, the best gift you can give a new romantic partner isn't chocolate or flowers: it's transparency about your finances.

By the time a new couple is on their third date, they should lay their cards on the table and "discuss your financial objectives for the rest of your life." Doing so, he said, can help stave off any unpleasant surprises down the line.

"Do you have any debt? Has your family been bankrupt? Do you have a brother that's gone bankrupt? All of these these difficult conversations need to be had before the marriage, before people move in together," O'Leary said. "Because within five to seven years, they'll manifest themselves as the reason you separate."

Though it can be a challenging and sometimes embarrassing thing to be honest about your finances early on with a romantic partner, O'Leary believes it will lead to stronger relationships.

"It's a business, that's what marriage is. It's a personal corporation," O'Leary said. "It's a partnership, and what's at the middle of it? Cash flow. Not very romantic, but it's the truth."

3. Teach your kids about money when they're young

By the time they are 6, children should have a basic understanding of money, O'Leary said. By helping a child have a "positive connection" with money when they are young, "you're doing them the greatest favor ever in their lives."

"Having discussions about money and how it's made at the dinner table is really, really important," O'Leary told CNBC Make It. "The concept of money saving and how the world works is something even a child can grasp at an early age."

Having a positive relationship with money is important, as is having a basic understanding of concepts like debt and interest. O'Leary said that his own children were well acquainted with the concept of debt when they were little.

"When my son was 6 and my daughter was 6, they knew what debt meant," he says. "These really simple concepts are important because it helps fend off the damage done by credit cards in young people's hands who don't understand what happens when they don't pay back their debts."

4. If you take a new job, prepare to commit your time

The biggest "red flag" that O'Leary sees on resumes is candidates who have been "bouncing all over the place."

If an applicant's resume shows them holding multiple jobs over the past two years, "I simply put it into the garbage, because we're not going to look at that person," O'Leary said. That's because companies invest money in training new recruits, and having an employee leave after just a few months is "a total waste of money for them."

"Have a mental commitment, whether you like [the job] or you don't, to stay there for at least two years," he said. "If you're asking to become part of a team as an employee and represent that company, you've got to have a minimum of a 24-month commitment."

Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."

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