The term "small business" is a bit of a misnomer.

There is nothing small about the pressure involved, having to hire (or fire) people wisely, and figuring out how to stay productive. In fact, it's a pretty big challenge.

That's something you learn quickly if you appear on Shark Tank and come away with your dignity intact. You have to go big or go home. The best ideas are the ones that can scale up and generate massive revenue. Just ask Barbara Corcoran.

The popular Shark seems to be the one with the most critical eye for whether ideas can turn into massive corporations. And she should know: She built up her real estate company to 1,000 employees and sold it for a cool $65 million in 2001. (Her latest business move is helping Canon plug its new Maxify printer.) I spoke with her recently about the importance of working smart and protecting your time when you're trying to build a business.

What are the biggest productivity problems facing entrepreneurs today?

I think the thing that kills any great idea is a lack of focus. There are so many products and services out there that are pitched as trying to help new businesses get off the ground, and it's hard to cut through the noise. Knowing the difference between what you need and what you don't is essential in making sure every minute of your day is used well.

How do you get more done in less time?

One, prioritize your "to-do" list before you leave at night and rate the items A, B, or C in order of importance. In the morning, I get my "As" done first. I figure out what's going to take time away from my business and eliminate things that don't work. Two, only take calls during the day from people you absolutely must speak with, and check your email twice a day. That keeps you from responding to endless emails that distract you and eat away your valuable time. Three, invest in products and services that are reliable, that have track records, and align their success with yours.

What other tools make business life easier?

Anything that improves your social footprint. Social media is such a huge part of doing business today, and it's hard to sell yourself or your product without it. I like posting on Instagram and Facebook to build brand awareness, and every time I do a Twitter chat, I use Hootsuite.

How do you think business will change in the next five to 10 years?

I think [going] mobile is great--there's an advantage to being able to be in touch from wherever you are. But there's this idea that we can all work from the beach or the backyard, and that's just not true. Lots of great ideas happen outside the office, but you have to spend some time indoors getting them done. All businesses should plan for mobile devices to make sales, because people shopping on their phones and tablets is the new norm. Mobile also levels the playing field and gives smaller companies the same access to customers that was once limited to big companies with a bigger reach.

If you could give founders only one tip about staying productive, what would it be?

Work early. If you get to work an hour before everyone else, you set the pace of your own day, rather than trying to keep up with whatever comes at you. I turn off my email when focusing on other tasks. That little "ding" that goes off every time we get a new message makes us stop what we're doing to answer that email, when it can always wait. That takes us off task, and that's lost time and productivity. And that's no good for business.

What usually derails your own productivity the most?

In business, you don't have to be good at everything. I built a business that employed over 1,000 people and I had no idea how to read a financial statement and I never learned. But I hired someone who knew how. In business, you only need to know how to access the people who can help you get to where you want to go. It's about having a vision--and an idea about how to execute that vision, and a sense of how to execute that vision through the right people. That's really important.

OK, settle this one for me: Is it better to email or call people with a business idea or to make a sale?

The phone call always wins.