Reading takes a lot of different skills. One of those skills includes figuring out what is important about a text. Another skill includes having an internal conversation with yourself about what you are reading as you read.
Over the years that I have been reading, I have learned how to decide what is important when I am reading. Generally, I will read with a highlighter and a pen. While I read, if I already know something I don’t highlight it. If something is new to me and seems to be a general and main idea of the text I will highlight that, and then I will look for details that go into more depth. Also I will note down a couple points in the margin that tell me what I have highlighted so when I go back I can remember why I highlighted that part. Figuring out what is important is somewhat of a biased decision. What is important to me may not be important to someone else. This is why it is important for teachers to go back and explain what they think is important as well. As long as the main ideas of the reading are understood, generally that will be enough.
Internal conversations are critical when reading and understanding what you are reading. I am always asking myself if I understood what I have just read. Also if I highlight things, I try to reword them in my head and if I write them down. This way I know that I understand it and if I come back to reread what I wrote/highlighted, and I can remember it a lot easier and faster. Also if I don’t know what a word is, I will have an internal conversation trying to figure out what the word means. I will reread the sentence that it is in and I will see if I know part of the word. Usually I can figure it out, but if I can’t, I will look it up in a dictionary.