Whenever I meet with entrepreneurs, I am always dazzled by their ideas, their energy, their capacity to imagine and create new things. These are all wonderful, even essential qualities. But they prove ineffective without focus.

The world is full of opportunities and ideas are cheap. You need focus to achieve and sustain real momentum. How do you get it? Here are the three things I consider most important to maintaining focus when you're running a business.

1. Get a good night's sleep.

We now know from sleep science that missing just one night's sleep reduces your cognitive capacity to the same extent as being over the alcohol limit. Moreover, when we're sleep deprived, we are more susceptible to rigid, stereotyped thinking. Our tired brain cleaves to easy answers, lacking the energy (or glucose) to search for novel ones. You could just say that being tired makes us stupid. If you want to be able to think creatively about your business, go to bed first.

2. Don't think of strategy as a balanced portfolio.

Many business owners imagine that having a multi-pronged strategy is a good way to balance risk. "If we try the business and the consumer and the kids' markets, then if one doesn't work out, we'll have the other." This is wrong, wrong, wrong. Most businesses are resource-constrained and have neither the cash nor the people to tackle more than one market at a time. Too easily, success in one subsidizes failure in the other, with the result that neither truly thrive. Reputation can't build because the market can't see--instantly-- hat you do and what you stand for. That "balanced portfolio" approach really says that you can't make up your mind. When VCs describe their "walking dead" companies, they're invariably referring to the small ones that tried to do everything.

Although focusing on one strategy at a time feels risky, the reality is that if the strategy fails, you find out quickly and unequivocally--and can then change course. You've learned something fast. Trying to do too much means you do nothing well and devote too much time to managing conflict.

3. Eliminate distractions.

Our brains have limited capacity and fundamentally do not, will not, multitask. They can task switch, jumping rapidly from one thing to another, but this is exhausting and inefficient. Learn instead to mono-task: Choose a task and work on it until it is done. You will find this remarkably efficient and less exhausting. If you call a meeting, make it explicit that smartphones and Blackberries are to be left outside. The work will get done faster--and better.

To concentrate, some people now use internet-blockers. The writer Evgeny Mozorov locks his laptop and cell phone into a safe over the weekend. Whatever your mode of techno-discipline, stick to it. When in doubt, ask yourself which you'd rather be: busy--or effective?