Those who markup their books with pens and highlighters

I read this book called "how to read a book" by Mortimer Adler.

He has different stages of reading; elementary, inspectional, analytical and syntopical.

I'm trying to do more syntopical and analytical. Syntopical is where you read many books at once on a certain topic.

Part of analytical is to do scribbles and highlights.

This is the part I would like to discuss how you do this.

Sometimes when I buy second hand books I love to see what the user had scribbled. One person had sticky notes in the book.

So when I'm annotating, it doesn't amount to much because I don't have the space to write my thoughts.

He mentioned using the margins and the back of the book.

So just wondering how you guys annotate and would love to see some of your pictures (if we can share images in comments)