I saw a badger at Point Reyes on my very first visit. I was wandering along, glanced over into the next field, thought “huh, that’s a weird rock”, looked through my viewfinder, and realized I was looking at a badger. I didn’t pay it too much mind, and kept working on photographing quail or something. I didn’t see another badger for 10 months.
I finally broke my badger drought last month when I saw two different badgers on the same day. And then again last week, I managed two badgers in the same badger hole! The one on the left is a nearly fully grown cub.
As far as I can tell there’s no real shortcut to finding badgers. I’ve seen advice like look for fresh diggings (darker dirt), but my most recent sightings have all been in fairly old holes. The main thing is spending lots of time in the field, taking a close look at all the dirt mounts, and hoping your paths happen to cross.