Here follows a treatise on how one ought to make one's characters appreciably different in every book, thus--
Okay, hold up. I just can't.
Sometimes authors want their characters to be similar from book to book. It creates a familiarity and sense of comfort for autobuy-type readers. Kind of like Jimmy Stewart and Harrison Ford often play the same character from movie to movie, there is a value to knowing what you're going to get when you open, oh say, a Dan Brown novel.
This is not me casting aspersions on Dan Brown, or Stewart or Ford either, for that matter. We like what we like.
Truth is, I wish the characters in my three books were more consistent. Can't tell you how many people have said they dug the protagonist in book one but either disliked book two or never even read it because the heroine wasn't anything like the book one heroine.
I suspect that the magic here is to find the character that resonates and then riff off that character as often as possible. Note that the first step is to find the right relatable character. Don't iterate on a crap character that nobody likes . Find your groove and then groove the hell out of it.
Or do what I do: stop reading reviews and just write what you love because you love it, and others may or may not follow suit.
