I reviewed this paper recently and it pertains to your question somewhat:
The effects of time pressure on chess skill: an investigation
into fast and slow processes underlying expert performance
http://home.medewerker.uva.nl/f.vanharreveld/bestanden/PsychResearch2007.pdf
Stronger players see all the important points of the position including the details. Stronger players have better heuristics; they play by better guidelines that pertain to a given position.
Heuristics and theory, time management, visualization, and motor skills are all important in blitz. The utilization of slow processes relative to your opponent is critical given players of equal strength; i.e. allocate your cognitive resources wisely in blitz so that you spend time on positions that are more critical.
I think that I recall from a study that the strongest players spend ~54% of time giving attention to pawn structure; I'm not so sure how attention is easily measured so I would be wary of completely trusting the statistic especially since processing occurs at conscious and subconscious levels and psychologists can only really measure observed behavior. Anyway, chess is an interplay of pawns and pieces and squares so I think that this is an interesting statistic.
"Blitz kills ideas." - Fischer