I have not read his book - 'Impro', though intend to. Here is part of an interview talking about his work and the book:
In the first 30 seconds of this interview you pretty much get the core of the method by which Sonny taught Eskrima -
Keith Johnstone says "Get rid of the fear"..... Sonny would say "Get rid of the freezing points"
"Make the right answers obvious" - This is what 'seeing' is.
"You have to fail" ..... There really is no learning without failing. Rote learning is not the same. You have to find the 'edges' of what you know to truly own it.
Don't be angry when you make a mistake, be happy .... Not Ha!Ha! happy, understand that mistakes may be gifts, so learn to surf them and use them to your advantage. Do not deny them.
"Learning to accept ideas is not good enough" .... Learn what your partner wants and give it to them. If it seems a little bit of a stretch to give your dueling opponent what they want .... think of giving them 'enough rope' instead ... But the key here is communication, not just playing by yourself.
Take risks ... "It's the goals you don't get that make it worthwhile ..." This is what training is for - it's a place to experiment, try, fail .... and gain skills.