When I read my textbooks, I highlight ideas or phrases that I think are the most important. I base what I highlight off of the headings of the section, and the first sentence of the paragraph. You can normally tell what the main idea of a paragraph will be by using those two tools. I do, however, go highlighting crazy sometimes, and highlight a lot of words on a page. When I look back at the reading, it can be hard for me to figure out the main ideas when the whole page is bright yellow! Another strategy I use when I read my texts is that I normally look for key words that relate to the broad heading or entire chapter. Sometimes texts put important words in bold face or italics, and then I pay closer attention to those as well.
When I read for my own pleasure, I read differently. Novels are not set up like text books, with headings or side notes in the margins. When I read for fun I find everything to be important. It is hard to tell sometimes what paragraphs or sentences are more important than others-depending on the genre of the book. I like to read James Patterson books and he writes a lot of murder mystery type books. Those books, I pay attention to the clues they find that I think will have more importance later in the story. Also, in general, I find dialogue important-when the characters have conversations it can be powerful for the story. In dialogue it is important to pay attention to the mood of the character and the emotions he or she possesses. I am also in the middle of reading Pride and Prejudice and since the language is more difficult at times I try to pay attention to the words I am familiar with and use context clues to figure out phrases or words that I do not know.
I have noticed that I do have a conversation with myself when I read. While I read textbooks I noticed that I ask questions to myself a lot. Sometimes I try to write them in the margins, but often I find the answers as I keep reading. When I am reading for fun I ask questions too-but the questions revolve around the plot and not about information I have just read. Also, I hear myself talking the words while I read and I paint a picture in my mind of the events of the story.