Begin practicing serenity and consciously not to worry. Worrying is like a rocking chair: it keeps you busy but doesn't change anything. Try to realize that you are unable to control the vast majority of things in this world. The only "thing" that you really have control over is yourself. So let things go their own way and focus on what you can change.
Here is the famous Serenity Prayer by Reinhold Niebuhr:
"God, grant me the serenity
to accept the things I cannot change,
courage to change the things I can,
and wisdom to know the difference. "
Start caring for a balance in your life. A balance between work, family, friends, social activity, and time to develop your personal passions. Never shift your personal passions to the last place.
Prioritize and plan the sequence. This will allow you to achieve your goals in a less stressful way as you have taken the time to plan them.
Start practicing caring for the things that matter most to you. It may sound very selfish, but it is really necessary. If you burn out, you will have nothing to offer to others. If you are not happy yourself, you will never teach your children to be happy.
Learn to say 'No' to other people and don't take on more commitments than you really want.
Celebrate the successes! Successes of yourself, family, colleagues at work. Even the smallest. This will help you develop and maintain a high level of motivation to achieve new goals.
ps. when was the last time you gave yourself a gift?
Work out regularly. This helps to relax both the body and mind, not to mention the endorphins (happiness hormones), which are secreted more with each physical exertion. According to scientists, 30 minutes of physical effort every other day is the optimal dose. And according to physiotherapists, each muscle group should be stretched at least once a week.
Build a support system. Look for friends, authorities you can trust. People who can provide you with wise advice and support. Cultivate these relationships.
Learn to take breaks consciously. You don't really have to do anything. When, for example, you start to feel tired or irritated while working at work - take a break. Take a step back, detach yourself from what is frustrating or discouraging you. Return to this activity when you feel better.
Use your sense of humor. Seriousness is a quality of the intellect. And you are not (only) the intellect. Laughter is great medicine, and the right attitude helps you see opportunities in difficult situations. For the more advanced: start practicing self-distance.