You want to be happy--everyone does. But what's keeping you from this state? Take a minute to scan your thoughts and emotions. Are you harboring worry, fear, resentment, guilt or envy? Obviously, these sentiments actively work against your level of happiness. Here are several simple ways you can adjust your thinking to achieve a higher level of contentment and peace, regardless of what's going on in your life.

1. Make peace with the mistakes you've made

You'll never experience real and sustainable happiness if you are unable to forgive yourself. "You were doing the best you could, given your set of circumstances, the amount of support you had and your level of understanding and insight at the time," writes Dannie De Novo, author of Get in a Good Mood and Stay There. "[I]f you learned a lesson in the process, then you are deserving of your own forgiveness, even if no one else will grant forgiveness to you."

2. Choose a positive story

Your psychological well-being also depends on how you react to the people in your life who have treated you badly. In Game Changers: What Leaders, Innovators, and Mavericks do to Win at Life, Dave Asprey suggests using gratitude as a tool to reframe a situation which triggers you. Imagine someone cuts you off in traffic, you feel indignation and the thought that "He thinks he's better than me." What if that story weren't true at all, and the person was instead rushing to the hospital to see his dying mother for the last time? If that story was actually true, you'd probably feel grateful to allow the person go ahead of you. "It's the feeling of gratitude for even a perceived slight that opens the door for forgiveness," he writes. "At its core, forgiveness lets you stop carrying other people's grudges. You have more important things to carry."

3. Acknowledge the many things you're probably taking for granted

In Success Through a Positive Mental Attitude, Napoleon Hill and W. Clement Stone quote the story of a woman whose only child, a 14-year-old daughter, died. Initially, the woman and her husband were consumed with why, sold their home and endeavored to escape their pain through extensive travel. She explains:

It took months for my mind to begin to accept the fact that all the joys of children and good health and security are blessings the Almighty loans to each of us. These infinite mercies which we finite persons presume to take for granted should each be cherished for their true meaning and great and irreplaceable value. How could I earn the right to keep my other blessings? How could I show my appreciation and thanks to Heaven for allowing me my husband's love, for living in this great nation of ours, for my friends and my five unimpaired senses, for all the good things that surrounded me?

What can you be thankful for in spite of your own losses and frustrations? Do you have your health? Is there another person on this planet who loves you? Do you have enough food and a roof over your head? Increase your gratitude and your happiness will follow.