A good idea is not enough – although it's a good start. Ingenuity and hard work are just as important as a good idea. Having said that, a simple idea can reap rich rewards.

A good idea also requires persistence. If you lose heart in your idea, you won't have the confidence to sell it to the banks, which you'll probably be asking to back you.

A good idea, plus hard work, plus a home life equals happiness. If you need to be convinced, check out You Can Have it All by Mary Kay Ash, who founded Mary Kay Cosmetics in 1963. She discovered the meaning of life–work balance before it became a buzzword.

A good idea plus business success doesn't always equal happiness. The creator of FM radio, Edwin H Armstrong, reaped more than £10m from his idea in the 1930s but spent the rest of his life struggling to protect it and committed suicide in 1954.

A good idea plus social responsibility can work. Body Shop founder Anita Roddick showed that you can make it in business and raise the profile of pressing global concerns, such as female body issues. She allegedly remarked: "If you think you're too small to have an impact, try going to bed with a mosquito."