You’re up for a promotion, but you’re wavering on whether you’ve earned it. You’ve been thinking about joining your local school board, but you’re worried that you don’t have what it takes to lead. Life is full of challenges that can nibble away at our egos and cause us to doubt ourselves. It’s human nature.

Self-confidence is our belief in our own abilities, qualities, and judgement. And the science is clear: Our beliefs are within our control to change—which means we all have the power to build more confidence.

Here are four proven ways to make that happen.

1. Start with a positive intention. Humans are primal creatures programmed to scan for threats, just like our days in the wild. That’s why it’s natural for us to stay vigilant by focusing on failure. You’re more likely to remember the one time you fumbled during a presentation instead of all the times you didn’t. Turn that instinct on its head by scanning for success instead. Say to yourself, “I want to feel more pride. That means I need to focus on what I’ve done well and the times I’ve met and exceeded my own standards.” This kind of self-affirmation builds up your “psychological immune system” and has been proven to increase self-confidence.

2. Make a feel-good list. Did you go above and beyond for a friend who needed help? Did you nail a memo? Have you gotten better about packing lunch instead of eating out? Write down every win from each corner of your life. Fold up that list and carry it with you (or keep it on your phone for easy access). Read it over next time you feel self-doubt creep in. Keeping track of your achievements is a great way to fight off the feeling that you haven’t earned your success, known as imposter syndrome.

3. Plan for confidence. Confidence needs to be built into your life, just like a massage or a trip to the gym. Ask yourself, “What’s one thing I can do to generate confidence today?” Set yourself up for a couple of slam-dunk successes to build momentum, whether it’s reaching out to a friend in need with a quick text or tying up some loose ends at work. You’ll be in good company: A study on Olympic swimmers found that “very definable, minor achievements” (like planning how to pace their swim) were crucial to a successful training routine, because each small win enforced the swimmers’ confidence and motivation to keep going.

4. Fake it ‘til you make it. When it comes to confidence, we need to feel it to believe it. Posture affects our body chemistry, thoughts, and feelings, as social psychologist Amy Cuddy has noted. When we feel powerful, we gravitate towards “high power” poses: We sit tall, take up space, and open up. When we feel powerless, we shrink and hunch over into “low power” poses. Ask yourself: How are you sitting or standing? How are you presenting your power to the world—and to yourself?

These changes in your body can literally change your mind. According to Cuddy’s research, high-power posers experience a rise in testosterone, making them more willing to take risks. Low-power posers, on the other hand, experience a rise in cortisol, making them more risk-averse. In Cuddy’s words, “Tiny tweaks can lead to big changes.” Honor the sense of accomplishment that follows. You earned it.

Kara Baskin is a Boston-based journalist and wellbeing expert. For over 15 years, she has been helping consumers live healthier, more fulfilling lives, writing for outlets such as The Boston Globe, Time, and Women’s Health. Kara has also collaborated on several books on women’s health and resilience. Find her on Twitter @kcbaskin