This is a means to an end (understanding the text) not the objective itself.
Try chunking the text for students the first few times. This allows students to learn to chunk text for themselves.
Review reading/decoding strategies with students prior to having them paraphrasing the text.
When students are able to use imagery, teachers will see an improvement with comprehension and retention of ideas. Have students visually represent the selected chunk as a picture or symbol. The use of non-linguistic representation (Marzano) is an example of this variation.
Have students clarify main ideas by summarizing the meaning of a paragraph using ten words or less.
After students summarize a portion of the text, ask them to respond to a few questions that will help them make connections and understand the significance of the text.