I took my first investing class as a teenager, and one moment stands out in my memory. A fellow student asked the instructor, a stockbroker, about dividends.

"Dividends?" he asked. "I'm trying to make my clients wealthy. You don't do that waiting for tiny checks in the mailbox every quarter."

Even then, I had enough horse sense to know he was wrong. Paying attention to dividends is exactly how you become wealthy over time.

Wharton professor Jeremy Siegel made a wonderful discovery in his book The Future for Investors. The greatest long-term returns typically don't come from the most innovative companies, or even companies with the highest earnings growth. They come from companies that happen to crank out dividends year after year. Simply put, since the 1950s, "the portfolios with higher dividend yields offered investors higher returns."

Market commentary regularly centers around price gyrations, yet dividends have historically accounted for more than half of total returns.

Reinvest those dividends, and the gains get even greater. Take Black Hills (NYSE: BKH), for example. Since the early 1980s, the company's share price has increased 925%. But add in reinvested dividends, and total returns jump to over 5,200%:

Source: Capital IQ, a division of Standard & Poor's. 

There's no ambiguity here: Over time, Black Hills' share appreciation alone has paled in importance to the power of its reinvested dividends. The results are similar for others like Consolidated Edison (NYSE: ED) and American Electric Power (NYSE: AEP); reinvested dividends skew both companies' total returns dramatically higher. If you're a long-term shareholder, don't worry about daily share wobbles. Devote your attention to those dividend payouts and your commitment to reinvest them.

And how do Black Hills' dividends look? At 4.8%, its yield is far above the market average. The company has paid a dividend every year for 70 years, and that payout has been raised every year for 41 years. As in most companies engaging in the utilities business, dividends use up the great majority of free cash flow -- if not more than it. This, though, is standard fare in an industry where high capital expenditures are rewarded with fairly stable income. Black Hills' track record of uninterrupted dividends bodes well for a future of above-average returns.

To earn the greatest returns, get your priorities straight. What the market does is less important than what your company earns. What your company earns is less important than how much it pays out in dividends. And what it pays out in dividends is less important than whether you reinvest those dividends.