To succeed with category keywords you must have an exploration strategy that values the rate of data acquisition. At my current workplace, we use a probalistic binary search model, that adjusts bids from very high to low in order to more quickly determine the expected conversion rate.

Outside of this more refined statistical method, what marketers can do to better find and exploit meaningful keywords on Amazon is deploy a more granular campaign structure. Because keywords define audience segments, each audience segment needs a different set of considerations in terms of aggressiveness and expectations.