Flag things to fix during review
one thing i do while doing my daily reviews: if i come across some incongruity or question while reviewing a card, i write down the question on the paper in front of me (i always have a scratch paper in front of me for e.g. writing kanji or expressions for math) and then i circle it (to distinguish it from scratch work). Sometimes when I'm reviewing, seeing a card makes my mind wander in a certain new direction, and that can lead to new questions.
then, after finishing my daily reviews, i go back to each question and i make new cards about them.
e.g. today i was reviewing the definition of C\_f(x) in algorithmic complexity (Li and Vitanyi), and i only had a couple of cards about this, and since it had been a while, i realized i didn't even know what x was! This sort of thing is hard to anticipate. So i wrote (on paper) a question asking what x was, and looked it up in the book, and added the same question as a new anki note.