I'm not a great fan of online networking sites. In principle they are a great idea but they now take up so much time that I believe they have become counter-productive.

However when I think about the business success that I've enjoyed, I can't overestimate the importance of building a network and using it to increase your knowledge base. Usually this is something that I try and do face-to-face or at least on the phone rather than via the internet but however you communicate these connections can be vital to commercial success.

Experience is a great tutor but if you have a gap in your knowledge it is a real benefit if you have a trusted contact that can help with advice and direction.

My involvement with Dragons' Den has means that I receive numerous pitches and presentations both on and off screen from people with business ideas and proposals. When I'm reviewing them one of the first things I look for is how much relevant experience the individual has in the market sector. If the answer is "not much" then I start to worry. Enthusiasm and commitment are essential but alone they are not enough. In most of these cases people need to fill their "knowledge gap" and that is where a good network and the right attitude are vital.

A number of the investments that I've made in the Den have been based not on what I know but on the contacts that I have and what they may be able to add to a project.

One of the best examples is Levi Roots, the inspiration behind Reggae Reggae sauce. He had a great product and an engaging personality but a major reason for my investment in his product was the fact that I have excellent contacts in the grocery business who were able to help him with the distribution that he was unable to get alone.

Over the years I've been lucky enough to build up an enviable contact base and I frequently have the advantage of being able to discuss ideas with people who are experts in their field this means that I can build up my knowledge quickly with high quality information.

Not everyone has the advantage of such contacts but the process of building a network is the same whether you have a relationship with the chairman of a bank or with the local branch manager.

I've developed my contact base through all sorts of connections: people I've worked with; some I've met socially; others are friends of friends; but it's always worth keeping that business card or the scribbled bit of paper with contact details. There have been many times that I've wished I could put my hand on a phone number or an email address of someone who I realised would have been able to help with a burning question. Fortunately I now have a wonderful assistant who helps me keep my contact base well ordered and up-to-date.

Nurture these relationships and be prepared to give as well as take information. Treat every contact as important because you never know when a connection will be useful in the future. Absorb all of the information on offer but try not to fall into the trap of accepting everything as accurate just because the source seems authoritative. Check and counter check as much as possible and soon you will build up the jigsaw puzzle that means you are well informed and have an edge in your decision-making.