Perhaps someone else has originally coined the title's term but nevermind. As an entrepreneur and as a human being, really, every encounter is an opportunity. You have a chance to understand, get to know someone and learn something new. You also have an equal opportunity to share, expand horizons and maybe even help them in some meaningful way. When you do this within your boundaries to people you like, that's maximizing luck.
You're also maximizing luck when you can spot different everyday opportunities. Maybe today you should go and play board games instead of that networking event? Why wouldn't you join Facebook groups relevant to your business? Who knows what would happen if you'd go and introduce yourself to that new storekeeper next door?
Of course, all that consumes energy and might be scary. And you shouldn't push yourself too hard because that's when you become inauthentic. Just expand that comfort zone bit by bit and cool things will happen.