WHERE TO LOOK

Postings will usually be on bulletin boards in businesses, or on telephone poles

If you're too lazy to look or put any effort into it you aren't gonna have a good time.

If you're throwing some big thing for profit, its pure business to try and reach as many people as possible, meaning you're gonna have to sift through some shit. You can narrow down your google searches by interests.
Instead of "Events in my town" try "music events in my town" "anime events in my town" "sports events in my town"
Whatever your hobby is insert there.

You can try facebook too. That's how I find most of the events going on in my town, but shocker, I still have to scroll past bullshit I don't care about. FB will let you narrow it down to things like "nightlife" "music" or whatever handful of other categories.