What have you learned over the years as the single best tip for long-run returns?

Mine has been this simple powerful concept:
http://www.finweb.com/investing/compound-interest.html

This just doesn't seem like a "long term strategy" ( --words taken from the title of your post). It's kind of like the strategy of choosing your parents carefully, or making sure to be born into a rich family. I don't have 30 years of life expectancy left. Even if I'm totally convinced of your "strategy" -- how can I follow it?

As for my own best long-term strategy, I suppose it would be constantly buying high quality dividend-paying stocks, and gradually shifting my investments into bonds, CDs, and high-interest-bearing bank accounts over time. I'm always fully invested. I don't try to time the market. I see the stock market as a way of generating wealth, and I see bonds, CDs, and high-interest-bearing bank accounts as ways of preserving that wealth. Even though the stock market has not produced an advance since I've been investing, since I'm not trying to time the market and have faith (hope?) that it will eventually turn upwards, I continue to look to it to generate wealth.

What have I learned over the years as the single best tip for long-term returns? I suppose it's patience. The importance of holding firm in the face of destruction of wealth. Psychologically, we are discouraged by what we see; but, logically, we reason that holding steady is the best thing to do. The best tip that I could give a beginning investor is NOT to act on emotion, NOT to follow the ups and downs of the market too closely, NOT to listen to financial "news," NOT to let emotion override reason; develop an investment plan and stick with it; study behavioral economics, and defend yourself against the feelings and emotions that we all have.

--SirTas