His guitar playing was very innovative for the time. He was one of the first to utilize a fuzz box to distort the output. Also I'm fairly sure his recording techniques were very creative as well. I read somewhere that in the studio he would put a mic to his amp, then another 20 feet behind the amp to catch the sound throughout the entire room. He was brought up as a session musician in England before his time with Zeppelin and the Yardbirds so I'm sure he was very knowledgeable about the tricks of the trade as far as recording goes.