It's not the insecure people you know who do well in life. Rather, studies have shown that that the adage "confidence breeds success" is true. Whether or not they're actually better or more skilled than others, confident individuals are perceived as more attractive and are better at sales because they're more trusted, particularly when money or resources are at stake. They're also more likely to be promoted and less likely to get called out for making mistakes. Do you want that for yourself? Be intentional and do what it takes to build your confidence muscle.

Use the five-second rule.

It's a concept created by Mel Robbins who wrote possibly one of the most motivational books I've read in recent years. Essentially, she says the key to getting ahead in life is pushing yourself to take action. It works like this: Whenever you have an impulse to do something, start counting down from five. Before you get to one, act. The counting and the quick movement keeps your brain from talking you out of speaking up at a meeting, exercising when you don't feel like it or walking across the bar to introduce yourself to someone who looks interesting. These kinds of actions--as opposed to inaction--are life-changing.

Travel more.

Traveler blogger Tom Keugler says he and other digital nomads have experienced the kind of personal growth produced by traveling. The new situations you find yourself in while away from home are character-building. It's because navigating a new place is rife with uncertainty and when you come through it, you're stronger, more competent and more confident.

Stop worrying about what others think.

The reality is they're probably not thinking much about you at all. And when you screw up, it's not as big of a deal as your mind would have you believe. Researchers have found that people often feel their reputation has been ruined when they fail at something, but this fear is typically exaggerated. The tendency to overestimate how badly others think about your mistakes steals your joy and causes you to be inhibited.

Work harder at being interesting.

What do you say when someone asks you what you do for fun? It's demotivating and derails your confidence when you don't have a good answer. Hang out with interesting people, stop watching TV and start doing stimulating things which will broaden your experiences, give you more things to talk about and bolster your confidence.

Pay attention to your appearance.

Like it or not, people will make a snap judgment about you within a few seconds all based upon what they see. Researchers have found that men wearing a tailor-made suit are perceived as more confident, successful and making more money, and women dressed provocatively in the office are rated less favorably than those who are more buttoned up. And anybody who's ever had a bad hair cut knows it takes a toll on a person's self-confidence. In fact, according to research conducted at Yale, people feel worse about themselves when having a bad hair day. Subconsciously you'll feel more solid when you look good.

Find a mentor who can help you see your future success.

Researchers at Ohio State University created a fake program to train students for the profession of "business psychologist." They placed students into four groups: a control group merely told about the program and three others in which students were told they exceeded the GPA requirement for the program. Participants in a third group received a bit more encouragement and were told they were perfect for the program and unlikely to be turned down. A fourth group was given the most validation and also told that they would excel in the program and graduate with multiple job offers. The latter group which received the most encouragement demonstrated more self-confidence when asked about their future as a business psychologist and were more likely to apply to the program. When it comes to your career, you can replicate these results by finding a mentor who can help you see your successful future and increase your chances of actually getting there.