I've studied happiness for 10 years, 10 phrases I use every day

I've spent the past decade immersed in the science of happiness, and I've learned that our relationships are the most important factor contributing to our personal well-being.

While researching my new book, New Happy: Getting Happiness Right in a World That Gets It Wrong, I discovered that there are two major barriers that get in the way of better relationships—and therefore a happier life:

We're never taught how to build healthy, supportive relationships, but it's a skill, like any other, that needs to be honed. We live in a world that makes it difficult to invest time into honing this skill and building relationships, which often ends up taking a backseat to work and other responsibilities.

Don't Miss: The Ultimate Guide to Earning Passive Income Online

Here's the good news: Your words have the power to make someone else feel seen, heard, and loved. By creating happiness for someone else, you eventually end up experiencing it yourself.

Here are 10 phrases I try to use every day to keep my relationships thriving and put what I've learned about happiness into practice.

Even in our closest relationships, we are often reluctant to share how we truly feel, because we are too concerned about being a burden or an imposition.

Asking this question lets the people we care about know that we want to hear about the wide range of feelings they are experiencing.

It also gives them an opportunity to use “labeling,” a powerful psychological strategy. Research has found that putting your feelings into words — such as saying, “I'm really stressed” or “I'm feeling a little down today” — makes it easier to deal with those feelings.

We use four types of questions in our conversations, according to researchers from Harvard University. The most powerful questions of all are follow-up questions that go deeper and ask for more information.

Inviting someone to expand on their thoughts or feelings shows them that we really care.

Taking a minute to thank someone not only makes them feel good, it helps us too. Studies have found that gratitude acts as a protective “stress buffer.”

For example, one study looked at couples who were facing financial difficulties: Grateful couples were less affected by these challenges and felt more satisfied with their relationships.

People around you contribute to your well-being in different ways — like a coworker who helps with a project or a friend who gives you thoughtful advice. Make it your mission to discover their efforts and thank them.

We tend to judge others' mistakes more harshly than our own, as when a spouse forgets to do a chore, a colleague makes a mistake in a report, or a friend promises to call but never does.

Try as much as possible to tap into your empathy and tolerance, realizing that making mistakes is part of being human.

Forgiveness is linked to improved mental health and better results at work.

Everyone we know is trying to achieve goals that matter to them — and facing challenges and setbacks. Our words of encouragement can inspire them to persevere.

For example, in one study, doctoral advisors wrote encouraging notes to their advisors, using phrases such as, “I want you to know that I trust you completely.” After a month, these advisors felt more positive about the relationship, were more motivated to continue pursuing their research, and were more interested in remaining in academia.

Our culture teaches us that pain is shameful and embarrassing. As a result, when someone we love is suffering, we may tell them to look on the bright side and cheer up. These well-intentioned comments can make people feel very lonely.

By validating people's feelings instead, we can offer them support in the moment and help them develop greater self-compassion.

It's so easy to take our most important relationships for granted. It's the result of a phenomenon called hedonic adaptation, where our brains are primed to get used to the good things in our lives.

To overcome this tendency, stop for a moment and imagine what your life would be like without this person. You will likely have a new awareness of how important they are. Don't forget to tell them.

All of these sentences, in essence, are different ways of expressing our love – but there is no substitute for the simplest and most clear phrases.

Every loving moment shared between two people has an impact, with studies showing that it enhances both parties' well-being, relationship satisfaction, and sense of meaning in life.

You can use these same sentences with yourself as well. Just as it strengthens your relationships with others, it can also strengthen your relationship with yourself.

Stephanie Harrison is the founder of The New Happy, an organization working to develop a new philosophy of happiness. She is a happiness expert, speaker, designer, and author of The New Happy: Getting Happiness Right in a World That Gets It Wrong. Follow her on Instagram, TikTok and LinkedIn.

Do you want to make extra money outside of your day job? Sign up for CNBC's new online course on How to Earn Passive Income Online to learn about popular passive income streams, tips for getting started and real-life success stories.

Plus, sign up for the CNBC Make It newsletter for tips and tricks for success in business, money, and life.