I don't know that is just one event that made my catch go up significantly, it's more of a culmination of things.
Good electronics is always a plus but back in the day when we only had flashers we still caught fish. The flashers showed you the same info it just took a bit of interpreting to figure it out.
We first started using GPS when the hand held models came out. It sped things up a bit when try to find our spots but we found our spots even when we had to triangulate with shoreline cover.
Fishing poles neither quantity or length didn't matter if you weren't on fish.
Time on the water helped but if you didn't know what to look for you could stay out there for days and not do any good.

I think the single most thing that helped me was the internet. C.C was a huge part of my education and also watching shows like Midwest Crappie & the many YouTubes contributed much to my success. You may have to pick around the BS but if a guy just came on here and looked through some of the old threads he could gain a lifetime of knowledge in a few hours time.