Blunders will hurt returns much more than brilliant moves!

This advice can save or make – us a lot of money. It’s simple: Just don’t make mistakes. Our investing success will be determined by the mistakes we make: by the number and the magnitude of our losses. Invest for long term, take what the market gives, don’t overreact when it goes down, and don’t mortgage your house when it goes up. Minimize expenses. Don’t take unnecessary risks. Have an investment plan, and stay with it.
Pretty basic stuff, to be sure. But how many of us consistently stick to these basics? (Abstract from Individual Investor)