To summarize for anyone who would rather not watch the video, there are always exactly 4 "events" in a wildwood instance. While any specific event is randomly selected, their locations are always around the far North, South, East, and West of the area. If you can find two events, especially if they're perfectly horizontal or vertical from each other, it becomes much easier to find a third and possibly fourth. After you find the first, all you have to do is look for the remaining spots of the 'diamond', following wisp trails to make an educated guess.

I thought this was pretty useful information, especially if you're trying to maximize wisp collection to juice your maps or find more nameless creatures to complete quests.