What is Donald Trump's best business advice?

"You have to think big. If you're going to be thinking anyway, you might as well think big! And never, ever give up. The world is vicious, it's tough. You have to be a killer. You have to go after what you want. Negotiate? I wrote the Art of the Deal. You have to be willing to walk away, but you also have to know when to close. Location, location, location? No, it's confidence, confidence, confidence!"