I use specifications as a guide to help me select suitable speakers.
Frequency response curves can be useful - where they're available. Sadly there are far too many speakers where they aren't. I'm not interested in speakers with a response that starts falling off at 100hz as I listen to a lot of rock and pop music and I prefer to hear those 44hz bass guitar notes. Also I'm not interested in speakers with a cartoon type bump on the head shaped part of the frequency response, which is most often found in the bass region - as the expression "one note bass" springs to mind.
Efficiency specifications. Every coned and domed speaker that I've heard with an efficiency of 84 or 85 dbs/2.83v/1m have sounded dead and undynamic. When listening to speakers like these, if I were to draw a volume graph in my head the shape would be like the roofline of a large factory. A series of flattened inverted "V"'s. When listening to more dynamic speakers the graph is much spikier and would resemble the shape of a heart-beat monitor, or a series of spears buried in the ground, pointy end up. Having heard too many undynamic low efficiency speakers, I've given up on them and now seek out high efficiency speakers - generally the more efficient the more dynamic.
Maximum Power handling. My preference for efficient speaker means that power handling is a non-issue.
Impedance. I'd be wary of using speakers with impedance that drops below 2 ohms as I don't think they would be good match for my amps which might not be too happy delivering that amount of current. Speakers like this are rare. I have a slight preference for speakers that stay above 5 or 6 ohms as these are more likely to work well with my SET amp. My solid state amp isn't too fussy about impedance.
Then there's speaker type. Single driver speakers, 2 ways, 3 ways, 4 ways, electrostatics all tend to have particular strengths and weaknesses. Sealed box, bass reflex, transmission line, dipoles, horns likewise. Small, medium, large.
The most recent pair of speakers that I bought were because of a single anecdote that I read on the Internet. This led to me doing some more Internet research on them which revealed that they have first class technical specifications and a first class reputation. I bought them without auditioning them. But then I never audition any hi-fi components before I buy them as I'm not into mainstream products.