I've read Austin Kleon's books so many times, but somehow I find new points to connect with each time.

Also have to highly recommend the Post-it brand "tabs" (i.e. reusable sticky page flags). They're really sturdy, very sticky but easy to reuse, and pretty cheap. They come in a bunch of sizes and colours, too. (They also have "flags" which are thinner and less sturdy—nothing wrong with those, I just really like how thick and durable the tabs are.)