What's the best way to find a dead cylinder?

Id be looking at bad wires or bad distributor cap.
Remember that especially these days new doesn't necessarily mean "good".
Which is why I buy new but old parts from swap meets, eBay, etc. stuff that was made when craftsmanship and pride in ones work meant something and you didn't have to ask " was this made in the USA?". There's plenty of "common parts" like ignition parts still floating around.
I have enough of that kind of stuff stockpiled that will last my lifetime.