Be conversant in the vocabulary of the blues; all the little licks, runs, turnarounds, walking tricks, and so forth. Know your history, and know that’s it’s far more than straight 3 chord 12 bar and Chicago or Texas shuffle. Know that a II chord or VI could pop up in the progression, understand bridge formats, check out the wide variations like Ray Charles’ gospel style ballads, blues that splits the difference with jazz like jump music, prison work songs, Leadbelly and Josh White’s folk, Jugband, New Orleans, Memphis, etc. Investigate the evolution of the genre from the 20’s, 30’s, and 40’s, city and country style. Just because you play in a modern band context, don’t overlook a recording from 1931 of just a guy and his guitar, because you may find “oh, that’s where that riff came from”. Listen to what the tuba players were doing a hundred years ago. Know Willie Dixon. It’s all DNA.
Frankly, Clapton’s performance and recording work since 1965, and before ‘85, is more pertinent.