The aspects of showmanship and performance really stuck with me. I often remember snippets of the book even today.
One of my favourite stories is when Derren is having dinner with friends and their child says "Show me a magic trick!" So Derren asks the child to name a card. He then flips over, by pure coincidence, the card the child named. Of course, he was planning on doing a more elaborate routine but he was present enough to notice that he would not be able to top his accidental trick and put the cards away.
He talks a lot about taking risks in performance and being attentive to the energy in the room. Of course, you need some solid reliable tricks as well to back this up!
His real genius is in identifying a kind of pseudo-scientific patter that would allow a skeptic to enjoy a mind reading performance. You can do the same crude trick that a mentalist or spiritualist would do, and wrap it in patter about neuro-linguistic programming and subliminal messages and psychology and with a few winks to let them think they're in on the secret and suddenly a hard bitten skeptic falls for the same sleight of hand trick that a gullible grandma fell for in the 19th century. Like, he accurately says that what he's doing isn't paranormal or "real", but his explanation on stage almost never matches what he's really doing.
I'm going to recommend another really excellent, long out of print book by a famous magician:
https://avalonlibrary.net/ebooks/Derren%20Brown%20-%20Pure%2...
It's an absolute gold mine of tips on performance and full of detailed technical explanations of how he did some of his most famous illusions. (and the answer is not NLP or subliminal suggestion or anything he talks about in his patter, most of the time).