When I was a High School kid, I spent as much time chasing them as I could. They made their spawning runs into the tidal creeks near my home in the spring, often starting in late February or March. I would cast small white or yellow wet or streamer flies for them, and sometimes added a small gold Colorado spinner blade & a few beads on my tippet ahead of the fly for added attraction & to help get them down. Perch would often run up into the shallow streams to spawn & retreat with the tide back down river to wait for the next high tide. The creeks I fished were shallow, but I knew some of the deeper areas.
I agree with Chuck about them relating to structure, as I caught many around the pilings of piers & downed timber.
Unfortunately, being a kid, my main interest was in catching fish, not how I did it! I've always enjoyed fishing with a fly rod the most, but at that time of year around here, wind is often a problem. I had no hesitation switching from a fly rod to spinning tackle when the wind made my fly casting difficult!
I also caught a fair number of Pickerel while fishing for Yellow Perch, even though they were incidental catches, I always enjoyed it! Usually, as the Yellow Perch run was ending White Perch would be starting their runs up into the creeks, and I caught them on the same flies!
In the last 30 years or so I've not spent much time targeting Yellow Perch, as the water warms up they become harder to find. Work & other obligations limits my fishing time mostly to the warmer months. But, I have caught them numerous times while fishing for other panfish species, and even while fishing for bass.
Dang, I miss being a kid!