People talk about serendipity like it's weather. It just happens to some people, not to others.
Serendipity happens when you put yourself in the path of it. That's the whole mechanism, and it's less mysterious than the word makes it sound.
The path — four plain steps, none of them lucky by accident
Go to the event by yourself. If you bring a friend, you talk to your friend all night. Go alone and you have to talk to the room, which is how serendipity happens.
Go hunt serendipity instead of waiting for it to find you.
Connect with others, not to extract anything — just be present, curious, easy to talk to. Most of my lucky breaks came through people, not plans.
Do those three things enough times and you start collecting a reputation for being lucky, when you're just positioned in the path of serendipity.