With the students in my self-contained class, I often have to simplify things. One way I might help a struggling student "see" the main idea is to teach that the first or last sentence of a paragraph might give you a hint, if not completely reveal the main idea. This is a quick activity I might give when working on this skill. I then created some additional support work so that the students could continue to work on identifying the main idea. I hope you find it helpful!