I read the first 1/3 of this book on the Azusa Street Mission revival the other night and I have a few take-away's: William Seymour developed the habit, before the revival hit, of spending 5 hours a day in prayer, alone with God. I don't mention this to shame the rest of us, but just to say, "wow". It's just something to get inspired over to maybe increase our alone times with God.
The second thing is that William Seymour was a very meek man. But he was not a weak man. Meekness is "enduring injury with patience and without resentment", according to Websters.
I think that any leader that wants to be used by God can learn much from Seymour's style or ways. Most people probably think of his message on the baptism of the Holy Spirit and speaking in tongues, but to me a big part of who he was and what he should be remembered for is his meekness. He could have bailed or crashed at any point from personal attacks. He seems to have understood that big time suffering will be part of the deal if you are called to be an apostle, but he was so caught up in sweet fellowship with Jesus that he could bear the suffering.