Peter Thiel defines luck:

What I do think is that as a society we attribute too much to luck. Luck is like an atheistic word for God: we ascribe things to it that we don’t understand or don’t want to understand. As a venture capitalist, I think one of the most toxic things to do is to treat the people I’m investing in as lottery tickets where I say: “Well I don’t know if your business is going to work. It might, it might not.” I think that’s a horrible way to treat people. The anti-lottery ticket approach is to try to achieve a high level of conviction, to ask: “Is this a business that I have enough confidence in that I would consider joining it myself?”

Here’s a story involving Donald Glover, recalled by his brother Stephen Glover (emphasis added):

Glover announced early on that he wanted to attend N.Y.U.’s Tisch School of the Arts and then write for “The Simpsons.” That seemed unattainable, but so did most of his desires. When Nintendo 64 came out, in 1996, his mother declared it too expensive. Stephen Glover told me, “I said, ‘Oh, well.’ But Donald heard on Radio Disney that they were giving a Nintendo 64 away to the ninetieth caller every day for a week. He listened all week and kept calling in until he gauged the perfect time, and one day he ran upstairs and said, ‘I won it!’ He’s always been able to will what he wants.”

In The Luck Factor, Richard Wiseman writes about three people who win a lot of competitions, Lynne (who wrote a column about winning competitions entitled Win with Lynne), Wendy, and Joe: 

What is behind Lynne, Wendy and Joe’s winning ways? Their secret is surprisingly simple. They all enter a very large number of competitions. Each week, Wendy enters about sixty postal competitions, and about seventy Internet-based competitions. Likewise, both Lynne and Joe enter about fifty competitions a week, and their chances of winning are increased with each and every entry. All three of them were well aware that their lucky winning ways are, in reality, due to the large number of competitions they enter. As Wendy explained, ‘I am a lucky person, but luck is what you make it. I win a lot of competitions and prizes, but I do put a huge amount of effort into it.’ Joe commented: 

People always said to me they think I’m very lucky because of the amount of competitions that I win. But then they tell me that they don’t enter many themselves, and I think, ‘Well, if you don’t enter, you have no chance of winning.’ They look at me as being very lucky, but I think you make your own luck … as I say to them ‘You’ve got to be in to win.’ 

I wondered whether the same idea might also account for the other types of opportunities that lucky people constantly encounter in their lives; whether this could explain why they often meet interesting people at parties and come across newspaper articles that change their lives? I managed to go backstage and discover the reality behind the illusion. And my research revealed that it could all be summed up in just one word – personality.

To summarize Wiseman’s findings, luck involves personalities that are high in extraversion, low in neuroticism (they have a relaxed approach to the world, enabling them to be more present and to notice the opportunities around them), and high in openness.