I've just been reading a terrific new book called High-Profit Prospecting by my friend and colleague Mark Hunter. Mark is a consummate sales professional, and his book is about how to keep your sales pipeline full so that you never run out of valuable prospects.

I'm not a sales professional, but I am an idea professional. And, just like I think it's vital for people in the sales business to keep their sales pipelines full, I think it's equally vital for people in the idea business to keep their idea pipelines full .

By the way, as a leader, you are in the idea business.

In his book, Mark talks about the importance of not leaving prospecting to chance, not just waiting (and hoping) for prospects to fall into the pipeline. He says that a true sales professional should have weekly (preferably daily) dedicated prospecting time scheduled on the calendar. Because keeping the pipeline full is that important.

Likewise, leaders should schedule time weekly (preferably daily) to fill their idea pipeline . Because it's that important.

So, how do you do this? Through four primary sources.

1. What you read.

There's a reason why Bill Gates, Warren Buffett, and Elon Musk read voraciously. They understand the value of keeping their mental pipeline full of new ideas.

"But I'm too busy to read, Bill."

Really? Busier than Bill Gates? Because he's pretty busy. And pretty rich. And he reads 50 books a year. I don't think these are unrelated. So, I'm sorry-what's your excuse again?

Schedule time to read. Every day, if possible. (And it is possible.) I'm not talking about Grisham and Patterson. They're fine for the beach. Read about ideas. Read about things you don't already know.

2. What you listen to.

To those of you who have horrendous commutes, congratulations! You've got a great opportunity to fill your idea pipeline! Instead of listening to the news (depressing), or the generic pop music station (mindless), why not try out one of the literally hundreds of great podcasts available? My guess is that there are at least a few podcasts out there for your particular field. Or, try one of my favorites, the TED Radio Hour podcast .

3. What you watch.

Although this probably won't help you with your commute, there's plenty to watch online-and some of it doesn't involve kittens. For example, in addition to listening to the TED Radio Hour podcast, you can watch actual TED Talks Or, if you want something more in-depth and academic, Stanford University (among others) puts many of their courses online, absolutely free.

4. Who you meet.

I've saved the best for last. There are actual people out there, freely roaming the earth, who have knowledge, experiences, and ideas that you don't have . They can be found in your town, in your workplace, sitting next to you on the plane or train. But here's the caveat: if you only hang out with the same people you always hang out with, you'll never meet these others. And that's to your detriment, as a leader, and as a human being.

So fill your pipeline! Feed your brain continuously with new ideas. It's the highest profit prospecting you can do.