Start with the author's TED talk. If you like her style and message, you'll enjoy more of the same in her book, plus some field research, like her entertaining observations participating in a Tony Robbins seminar.
I would have been fine just sticking with the movie and Wicked. I don't feel compelled to read any of the sequels. Maybe I would have enjoyed it more if I'd first read it as a kid.
The Final Empire was the first Brandon Sanderson book I had read, and I read every Mistborn book published so far (through Bands of Mourning and Secret History) almost back-to-back. The series is exceptionally enjoyable, with a fun magic system and compelling characters and story.
If this first book had been the only Mistborn book ever written, I think it would have stood well on its own. For anyone daunted by the prospect of starting a new series with six books and counting so far, you could read this one and stop. But once you've read this one, you'll probably want to keep going.
I was already familiar with Dweck's fixed vs. growth mindset framework, and I am a big fan of it. Unfortunately, I did not enjoy reading this entire book about it and found myself skimming or skipping over long sections or chapters on topics I was less interested in reading.