Lost the Basics?

Mary Kay Ash writes in Chapter 15 of her book The Mary Kay Way,

"Over the years, we've developed tools for success that have worked for thousands. You wouldn't expect a student to study algebra without first learning basic mathematics. The same logic applies in our business and every business: You must master the basics before you can proceed. But progress cannot mean an abandonment of the basics. Too many people find themselves in trouble when they stray from the basics that were responsible for their earlier success! Time and again, I've seen both salespeople and leaders start off brilliantly only to falter somewhere down the road. Why? Because they didn't stick to the basics."

What is a "basic" that helped you gain success you when you started your business?