Interactive Reading takes many forms, but the element that they all have in common is that the reader participates in a one-sided discussion with the author. Many readers used post-its to write down their comments while they read, and insert those post-its into the book and the relevant point(s).
Five common types of comments are:
Question: Ask the author, or even a character, a question. "Does this person speak with an accent?", "In what kind of setting does this scene take place?", "Why did you write such a detailed description of a seemingly unimportant event?", "Why do you (character) even like them (other character)"?
Opinion: Express your views on something included in or related to the content. "That interaction is unrealistic -- strangers don't talk like that to each other" "You've captured exactly what a sunset looks and feels like to me." "You are confusing me here. How does this scene even fit into the story".
Summarize: This is the simplest one, in my opinion. You simply restate a portion (paragraph, page, chapter) of the story. "Lennie sneaks into the bunkhouse and spends time with the puppy", "Ender becomes an outcast because of his exceptional abilities", "Harry looks into the Mirror of Erised and sees his family"
Predict: Indulge the sleuth in you, Sherlock. "Oooh, I bet that her untied shoe will eventually cause a problem", "I wonder whether the intensity with which she hates him will invert, and she actually ends up really liking him", "He noticed the kid in the red hat stealing the candy -- will that matter later?"
Connection: Explain a way in which one thing (or person or place or interaction) related to another part of the book, or part of the world, or part of your life. "When Ender has to choose the drink in the Giant's Game, it is just like how he has to choose between whether or not (or to what degree) he will be like Peter or Valentine", "The people being sorted into factions is similar to stereotyping in our school".