This book is very shallow and basic. I skimmed through most of it, because it contained little that wasn't obvious to me. If you already know that, for example, triggering stereotypes is a quick way to get readers to "fill in the blanks" about what a character is like, then most of this book is not for you.
There are not a lot of actual writing examples used, and the ones that are present are used to help explain his point rather than to illustrate a technique. This is not a book on technique, it's about a high level description of various things relevant to characterization. As a random example, the section on "raising the emotional stakes" starts out with "suffering". Card explains that the more you repeat suffering the less emotional impact it has, and that suffering is more effective when you know its specific causes and effects rather than just describing it. This applies equally well to pretty much any source of emotional impact, such as love, so there is no real idea unique to suffering. Card likes to take general writing truisms that are perfectly useful in themselves, and inflate the page count by wrapping them in overly specific examples.
Don't get me wrong, there is some useful stuff here at the "writing 101" level rather than the "remedial writing" level, but it's a minority of the book and it's sometimes well hidden. There's a very short section on the contract with the reader which makes the basic but useful point that the reader assumes the start of your book is important. Don't put throwaway stuff in the first few pages, if something isn't going to reappear don't give it depth and background right at the start. I've seen people make this mistake - but I was left wanting an entire chapter on this part of the contract with the reader, rather than one page. A complete neophyte writer could use it as a reminder of what they already know, to help them spot any obvious mistakes in their work.
He also has some pretty obvious biases, to the point it's difficult to see who his target audience is. He's an SF writer, but the book seems to be completely aimed at a mainstream "commercial fiction" audience. It seems unsuited for SF or literary fiction. It seems most suited to action, thrillers, or the like because Card describes the reader as a pretty unsophisticated, mainstream, lazy person.
Here's one example. There's a section about characters we love and characters we hate. It starts out with the useful tip that although people like attractive actors in movies, making everyone model gorgeous in books can actually hurt because readers feel inferior. He spends a bunch of time on how you can use minimal physical descriptions of the protagonist so people will fill in details of their own appearance and sympathize more. There's absolutely no coverage of how this is genre specific - some characters should be seen as attractive, repeatedly, because it's important that other characters react to them as attractive. Certain blatant "hero" roles, especially in speculative fiction and romance, call for this. This is typical of the entire book - Card assumes you're writing in a genre where identifying with the character is more important than making them remarkable.
That very same section on characters we love/hate is mostly structured as "here's a simplistic portrayal that readers may not actually like, now here's one example of a way to make it more sympathetic". There's a section on insane characters that says it's incredibly hard to make them sympathetic (with a lazy example of a complete lunatic), which then turns around and says you can make them sympathetic if their insanity is caused or perpetuated by someone else. Even completely delusional characters get an example of how to make them sympatheric.
Who doesn't get an example of how to make them sympathetic?
Smart people. There is a very short sections on "cleverness" as a trait we love, which just says be careful that cleverness means solving practical problems because if he flaunts superior knowledge or acts as if he knows how clever he is, the audience will think he's arrogant. "Intellect" is actually listed under traits we love to hate. Apparently to make a good villain, it helps to make them sound educated. The American audience supposedly resents any character who is smarter and better educated than other people, and the guy who wrote the "Spenser" detective novels faced the problem that "for every line of poetry, Spenser has to work out half an hour in the gym to win our forgiveness for his erudition". End of section.
This is frankly bizarre coming from an SF author whose most famous book is about a child prodigy who uses brainpower to show up the other kids (if I recall correctly, his siblings also posed as internet philosophers).
Reading this book you'd think that Spock must be the most hated character on Star Trek and nobody could stand Girl with the Dragon Tattoo. You'd certainly have no advice for dealing with the fact that SF books, and for that matter many mainstream SF movies, have "the smart character" or even "the genius" as part of the cast. And that many books, absolutely including literary fiction as well as SF, are written for an audience that is more knowledgeable and proud of it. The reader might want advice on how to write really smart characters without having them be seen as arrogant know-it-alls. There are some obvious ways that writers have done that. One is to make them a bit of an "outsider" so they can show a lot of intelligence without that implying that they're strictly superior. For example, Spock's unemotional philosophy means that he rejects many things humans value. No matter how smart he is, that doesn't mean he's beating us at our own game. Some characters go so far toward intellectual they become weak at other things. The genius who is brilliant but socially inept. The scientist who is very smart, but is stuck in an action movie where that doesn't get you the leading role. Or the absent-minded professor who is just so dorky and likable that he couldn't possibly be the hero, but can tell people what dumbasses they're being.
It took me five minutes to think of examples of how popular TV and movies, let alone books, have sympathetic intellectual protagonists. Card just says don't do it. I was not impressed.