19/03/2014 08:42 GMT | Updated 18/05/2014 06:59 BST

(A Practical Guide to) Confidence

I recently came across a quote by Mahatma Gandhi who said: "Man often becomes what he believes himself to be. If I keep on saying to myself that I cannot do a certain thing, it is possible that I may end by really becoming incapable of doing it. On the contrary, if I have the belief that I can do it, I shall surely acquire the capacity to do it, even if I may not have it at the beginning."

It made me think of a conversation I had with Helena Morrissey, Chief Executive of Newton and the founder of the 30% Club, on the subject of women progressing their careers in the corporate world. She said that no one was going to hand you over a promotion on merit alone. It is vital to have the confidence to pursue new opportunities, put yourself forward and build support networks within your organisation and across the industry. Confidence... Is it perhaps the catch?

"It's easy to feel confident when we're on a roll, when the cards are going our way, or we're closing sales right and left", says entrepreneur and author Seth Godin in his daily blog. He refers to this confidence as 'symptomatic confidence', a by-product of success, which isn't particularly useful. Clearly, people who lack confidence, and women in particular, need confidence, which comes from within and eventually leads to success at work, career progression and fulfilment.

To build up confidence from within we are advised to put it on and wear it "like make-up" and "fake it until you make it". Although eloquent on paper, such advice isn't particularly useful. Is there anything more practical to help us feel more confident ahead of a nerve-wrecking interview or an important presentation?

Yes, there is. I've recently heard of a confidence trick involving "power posing", made popular by a social psychologist Amy Cuddy, who gave a Ted talk on the subject in June 2012. Cuddy conducted research on how body language affects other people's perceptions of us. She recommends adopting a "power pose" to demonstrate competence and power, even when you don't feel confident.

"Stand in front of a mirror, put your hands on your hips, tilt your chin up, and make yourself as tall as you can get. Even better: throw your arms up and out."

Cuddy found that "power posing" for two minutes was enough to affect testosterone and cortisol levels in the brain. When your brain sends less cortisol (stress hormone) and more testosterone through your body, you look and sound more confident, passionate, authentic and captivating. In other words, the way you hold your body can change how you feel about yourself and how others perceive you.

A more permanent solution would be to build up confidence reserves over time. I recently had lunch with a managing director of a media company, who was telling me about being invited to an industry panel at a prestigious conference. "I get invited all the time, but I always decline because I fear I don't have the confidence to speak about the industry or even my personal take on it." This came to me as a complete surprise, coming from a person with a couple of decades of industry experience, well regarded by her colleagues and peers.

To cultivate longer-term confidence I was advised to simply say "Yes" to opportunities and build it up from there. Accept an invitation to speak at a networking dinner, say "Yes" to give a presentation at work or a local school, volunteer to write a piece for your organisation's intranet. Travel writer and Telegraph columnist Sophie Campbell agreed to take part in the Ladies Who Impress event Confidence even though public speaking is, by her own admission, just outside of her comfort zone.

It is vital to challenge yourself, if only to find out what a small brave step could do to boost your confidence to take on the world.