The author of this experiment noticed certain habits of lucky people, and had people do exercises designed to get them to think like lucky people.
The result?
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“One month later, the volunteers returned and described what had happened. The results were dramatic: 80 per cent of people were now happier, more satisfied with their lives and, perhaps most important of all, luckier. While lucky people became luckier, the unlucky had become lucky. ”
http://www.telegraph.co.uk/technology/3304496/Be-lucky—its-an-easy-skill-to-learn.html
Really interesting read.