A former Watford FC board member has written a new book about business, after becoming a self-made millionnaire before he turned 30.

David Lester, who spent six years at the Vicarage Road club between 2000 and 2006, started his own computer games company, Impressions, aged 22.

And he became a multi-millionnaire less than eight years later when he sold his business.

He now runs the UK's most popular website for small businesses, startups.co.uk, and hopes his book, Starting Your Own Business: The Good, The Bad, and The Ugly, will help aspiring entrepreneurs to avoid the mistakes he made.

He said: "I've wanted to write a book for the past five years, and it's taken four months to put together. All the business mistakes are mine but that's what sets it apart. It's hard to get people to talk about their mistakes but you learn more from mistakes than successes.

"A lot of people start businesses being good at one thing but they've never put a business together before. These things take a while."

Originally from Pinner, David went to Merchant Taylors' School in Northwood before studying economics at university.

He became an accountant but soon decided to write and sell computer games to make extra money. He began Impressions in 1988, and what started as a hobby became his full-time job in December 1990.

Three years later he moved to offices in Boston, where he stayed for five years until he sold his business for a multi-million pound figure "more than ten, less than 100".

He said: "I got out at a good time. It was a huge learning curve. I had to learn how to manage people, to budget and to listen to customers."

David, 41, is now a "business angel", investing money into failing companies. He is chairman of Portfolio Books, a distribution company for travel and non-fiction books, which has a turnover of £5million, and is behind One Small Step, a children's shoe retailer, and startups.co.uk.

He left the board at Watford Football Club in 2006 after being part of a "fairly turbulent period" in the club's history, and now lives in Kew, London, with his wife, Sue, and two children, Oliver, six, and four-year-old Jonny.

But he said being successful was not about driving a nice car or where you go on holiday.

"Money is good but there are many unhappy wealthy people," he said.

"You can drive a nicer car, have a bigger house or pour money into a football club, but the biggest thing for me is going out and making something work.

"Achievement is giving pleasure to people from games you've sold or helping to set up a business. That's definitely the biggest accomplishment.

"A lot of times I thought Is it worth carrying on?' It's never a bed of roses. The people who do succeed are people who find a way through and overcome these things and that's what I was able to do."