Unfortunately I probably don't have much of anything that'll be useful. The genesis of that book was that I was on sabbatical and had decided to get a job again

Unfortunately I probably don't have much of anything that'll be useful. The genesis of that book was that I was on sabbatical and had decided to get a job again, so I interviewed at a ton of places. I took a lot of notes for my own sake, and when I saw how many sales the most popular PM interview book on Amazon was getting, I figured if I even got 10% of those it'd still be worth my time to compile the notes into a book. In terms of general tips on writing this kind of thing, I just start with a big Google Doc and start writing sections about whatever's on my mind. If I'm thinking about a particular interview question, I write about it and leave it with some kind of a note to make it easy to find when I'm searching later. Once I've got a fair amount of content, then I start organizing and filling in the rest.