The goal I have is not to have anyone locally that's on all of the social media platforms often to say they didn't know.
I go hard, relentlessly and vigorous in my promotions, starting early and often. I manipulate the algorithm to my favor, ensure it's visible if it's a public event. I also have multiple people doing the inviting, which means inviting all of their friends and then their friend's friends. I do this early and often.
I ensure that my pictures of the event are shared daily in stories, posts. I post during the peak hours: mornings and evenings and days (Sunday evenings through Thursday nights). I discovered that's when folks are checking out what's in the air.
I have also found Eventbrite to be an awesome source. Outsiders may moss ads but they can subscribe to Eventbrite notifications and know months in advance.
I have seen this work and have attendance increase by 50%, complaints reduce by 75% and overall visibility is at 100%. I don't ever want to be mad at the results from the work I didn't do. Read that twice.