Karren’s success over the years has been born of passion, vision and ambition, but realised through determination, hard work, and a clear set of rules consistently applied in every aspect of her life and career. Learn the secrets of that success by clicking on her 10 rules below.

1. WORK HARD

I work relentlessly to achieve a business goal. I believe that is the single most important reason for my success. It may be 2am, I may be exhausted, but I keep working until the job is finished. It takes self-discipline and energy, but you won’t meet anyone successful who doesn’t have them both. The good news is that it’s like a muscle; you can train your ability to work hard.

But in order to push yourself, you have to really want it. If you don’t, you’ll never summon up the energy when you need to. So pick a career where you won’t want to do anything else. Very often it’s that ‘care about’ factor that underpins everything in your life, be it your business, your friends or your family.

That’s the sort of enthusiasm I look for in my staff. I have it myself and I don’t employ anyone without it. Remember: to be able to work hard and persistently is a quality that not a lot of people have. You stand out if you’re prepared to do the stuff that’s not much fun.

2. HAVE CONFIDENCE

I’m confident, and it has helped me at many points in my career. I know that lack of confidence can be an issue for a lot of women. But remember – practice builds confidence. I like people who walk up to me at networking events and say: ‘I came along because I really wanted to meet you’. So I think the best advice if you feel you don’t have the confidence to do something is to ask yourself, what have I got to lose?

I remember when my sister-in-law didn’t get a place at her chosen university. I said, ‘Why don’t you turn up and talk to them and see if you can get in? What’s the worst they can do? You don’t have the place anyway, so what difference would it make?’ And so she went, and they gave her a place. Who dares wins!

Confidence lies at the root of personality. I meet a lot of well-educated professionals who don’t have any personality, and therein lies a problem. People do deals with people, not with brains. When you’re choosing between two people with the same skills and qualifications, you pick the one with the personality you want to work with. Of course, there’s a fine line between enthusiasm and delusion. Success is about ability as well – there are lots of people who are very confident but they can’t deliver.

I’ve met some leaders who have refused to hire good people because they worry they may put their own position at risk. These are my least favourite type of people. If you care about what you do, you want to employ the best, and that may well mean you employ people better than you. But in doing so, you have shown your strength as a leader.

3. EMBRACE AMBITION

‘Ambition’ can be a bit of a dirty word. People think there’s a very fine line between ambition and ruthlessness. I don’t. I think if you’re ambitious, don’t be afraid of it. Ambition is simply the spark that drives you on to be, and keep being, successful.

A lot of people say to me, ‘I hate my job,’ but don’t do anything about it. If you think you do a good job but it’s not being recognised, what are you going to do about it? Ambition is about deciding what you really want to do, committing to it, then working out how, realistically, you can get there.

People can be shy of approaching their boss with ideas. But good bosses love nothing more than people saying, ‘I’ve got this great idea and I know how to implement it and this is the effect it’ll have on the company.’ It’s all about taking that first step. Believe in yourself, and make others believe in you and your ideas. Keep that up, and one day you’ll find yourself the one making the decisions.

4. Have the courage to take a risk

I think I’m naturally brave, but courage is absolutely something you can cultivate too. When I was asked to do Comic Relief Does The Apprentice, how could I have known it would lead on to my doing the interviews for the main show, then becoming one of Alan Sugar’s advisers? Calculate the worst thing that can happen and be comfortable with it. Don’t be afraid of things going wrong. Before you achieve success you nearly always face temporary defeat – sometimes total failure – and the easiest thing in the world is to just walk away, or simply not bother. Those who succeed find a way through.

West Ham has been a good example. We took a massive leap of faith in bidding to move to the Olympic Stadium, but now we have the most exciting future of any club in world football. The hardest fights are the ones really worth winning. I believe you regret only the things you don’t do, not those you do. You get one life and one career. Don’t end either asking yourself: ‘What if?’

5. Take a reality check

In setting your goals, you need to be realistic about your talents. I love art, but can’t draw, so it would never have been the right career for me. But sometimes you can take your greatest skills for granted. Many women come to me and say, ‘I’ve been stuck at home with the children for 10 years and I don’t know what I’m good at.’ Well, for a start, you’re organised, can budget, and can manage people well.

It’s not the first job you get that matters: it’s the last. You want to work in a certain company or a certain environment? Take the first job available and work your way up. And when you DO reach the top, you still need to stay realistic. You can’t pursue your big ambitions until you’ve fixed basic problems, sorted out weaknesses, pulled the plug on things that aren’t working. Lots of leaders avoid this because it’s difficult, takes energy, and can make you unpopular. It’s far nicer to be liked than not, but you can end up compromising your beliefs, way of doing things and, ultimately, chances of success. Always remember that you got started by being realistic with yourself, your goals and the steps you needed to achieve them. You owe the same to any team or organisation you lead.

6. Learn to juggle

If you have a family and a career you’ll need to learn about efficiency – and fast. You’ve got to be able to get your work done and get out of the office, but you’re competing against others whose working hours can stretch on indefinitely.

Organisation is the key. When I’m in the office I work relentlessly. I don’t surf the Internet, or waste time chatting, because I know when it’s all done, I can go home.

Dealing with things immediately as they come up is a habit I notice in many successful people, including Philip Green and Alan Sugar. If someone emails me wanting an answer, it’s much quicker to read it, answer it and move on to the next thing. I put all my emails into categories: one for urgent, and then others, for my various businesses. Then I take care of them in order of priority. There’s nothing more satisfying than getting to the last one.

At the end of the day, I frankly just want to be at home. So it’s OK to be picky about the social invitations you accept. Ask yourself: do I have to be there? Can someone else go instead?

As a parent with a career, you can’t be there all the time. Don’t beat yourself up. Listen to your children; they will let you know if they need more of you. Accept that you can’t do everything, and ultimately, you’ll be make the right decisions at the right time about where you need to focus. Most important, it’ll make sure you never waste a second of the time you DO have.

7. Plan to win

My organisations are run with military precision. Nothing is left to chance: people know their specific job, and they know exactly what they have to deliver. That creates an environment of relentless energy.

When I discovered I had a brain aneurism, I broke my response down into five steps: 1. Accept I had it. 2. Choose the procedure to deal with it. 3. Get it done. 4. Recover. 5. Get on with my life.

You can approach business challenges in the same way: break them down, work out the steps to the solution and resolve each one, step by step. In football, for example, if you want to win the league, by Christmas you need to be in the top five, and by Easter in the top two. Each one of those challenges becomes a project in its own right.

In the office, I like to get everything up on a board so I can visualise things more easily, and work out what needs to be done, by when, and who’s responsible. In the end, though, you need decisions, and that comes down to leadership. You can have the best team-work and planning in the world, but ultimately, it all falls apart unless the boss is prepared to take a decision when the pressure is on.

8. Know how to negotiate

I love doing deals. I’m resilient, relentless and persistent. Negotiating is not about being tricky. The way I see it, when you’re doing a deal you go in, you do the best you can to represent your company or yourself, have a clean fight, and at the end of it be able to shake hands and walk away.

The first rule of negotiation is to work out what you’re prepared to accept in advance and stick to it. No one ever starts where they want to finish. You’ll do your best deals when you have that mind-set, because the other person will recognise it, and put more on the table. I’m much more likely to walk away from a deal than many of my other colleagues, because I don’t mind saying no, and I don’t mind a tough negotiation.

Good negotiation is also about persuasion. When we’re doing a deal for a footballer, we have more to offer than just money: an ethos; an exciting future; an amazing fanbase. But I always remember there are alternatives. The worst possible mind-set to have in a negotiation is to think: ‘I have to have that, I can’t have anything other than that.’ There’s always another option to help you achieve the same goals.

9. Grasp the bottom line

The best businesses, whatever their size, have a small-business mentality. In my companies, anybody who wants to order anything has to get three quotes, and if they don’t want to go with the cheapest, explain why. This keeps everybody thinking about the bottom line. That matters because no organisation can succeed without a clear business strategy, a sound financial model to deliver it, and the resolve to take tough decisions to stick to both.

At West Ham, we put in five years of hard graft to get our finances in shape and make our business strategy viable. Success has meant increased investment in our playing squad, and big cuts in season ticket prices for our fans. But we know we’ve still got to carry on in the same vein for another five years.

Most people haven’t got a clue about their company’s finances. Have an eye for things that will make and/or save money, and you’ll stand out. As a manager, you need to engage your staff with the financial side of the business and train them to think like entrepreneurs. Update them on where the company is, what contribution each department is making, and the importance of keeping an eye on costs.

In my businesses I always have a cost committee, where junior staff watch what more senior people do in terms of expenditure – and they earn a percentage of everything they save as a bonus. It creates real openness and gets people thinking about the importance of saving money. The result is a better, more profitable company.

10. Communicate

Ultimately, a lot of managing people boils down to managing expectations. You do that through communication. In that respect, it’s very much like having kids: you have to set ground rules! But unlike with your family, you should be prepared to say, ‘I’m afraid you’re not delivering and it’s time for you to go.’

The people who work for me know exactly what is expected of them: they know what I think, where we’re going, and what the rewards will be when we get there. That’s because I’m very straight. I can’t stand people who say one thing and do another.

It’s also really important to get your messages right. Very often, you’ll need to adjust your public message for your staff, your customers and your shareholders. To communicate effectively with all these groups, you hire the best press officer, form the right relationships – do whatever you need to do.

People want to know you’re doing everything you can to run the business efficiently, and have faith in your ability. If there’s a problem, they want to hear: ‘I can resolve this, and here’s how.’ What they want, above all, is hope and belief in the people, the plan and the strategy.

Likewise, I believe that, as a manager, you should do your own dirty work. I hear stories of managers who have an issue with a member of staff and ask HR to ‘have a word’. I think that’s all wrong. If you have to confront someone, decide what you want the outcome to be, then deliver it yourself. You don’t need to get angry or macho. I prefer to just to tell people that I think they could do – and could be – better. The effects can be amazing.