Yes -- opportunity knocks. Everyone knows this. What you may not know is that it doesn't knock like the police, who bang so hard that it seems they're trying to break down your door.

When opportunity does knock, it knocks super-lightly -- and leaves after that first knock.

Opportunity most often doesn't knock at all. It walks by casually, not drawing any attention to itself. And it will only stop if you proactively approach it and convince it you're worthy of attention.