Do things, tell people
Luck = [Doing Things] * [Telling People] The more things you do multiplied by the more people you tell, the larger your Luck Surface Area becomes. The larger your Luck Surface Area, the more likely you are to catch luck as it flows by. 1
You can get away with just doing one of the two, but that's rare, and usually someone else is doing the other part for you. 2
This aligns with my experience. Currently I mostly do things, but don't tell people, and unsurprisingly I come up with a lot less interesting opportunities.
I think there's corollary to the above formula. The opportunities enabled by the "Luck Surface Area" only arise because there's someone on the other end picking up what you're putting out. So you can also increase your own "Luck Surface Area" by engaging with those who are "Telling People" (perhaps via some praise or helpful feedback).