To help students understand the purpose for asking them to work with me I explain what I have noticed. I tell them that when I look at their work, I have see them underline too many details in a text. Underlining is supposed to help them find the main idea or key details. This group of students almost underline everything.
I ask them to tell me why they underline when they annotate. They know it relates to the main idea or gist of the section they are reading.
Now they know the why. I ask them to watch me underline correctly. I model under the document camera how I read all of paragraph first, and then go back to underline. I then model how picky I am about the details I believe are the most important. I then ask them to tell me what they observed. They are good at picking out the expectation of underlining carefully.
To make my point further, I also model how not to underline. I read the same paragraph, but underline almost everything. I again ask them what they noticed. I put the two paragraphs side by side and have them compare and contrast them in a discussion.
The discussion helps me judge how much more modeling is needed. When I feel confident that they understand what I am expecting I hand out a paper that holds small passages. I found a very old worksheet that had little mini biographies on it. You could use a newspaper, or pieces or articles for them to practice.
The variation will help them practice the skill each time they read. If you use an actual CLOSE article they might go back to underlining everything. That is why I chose small mini passages. I ask them to only underline the most important details. I challenge them to underline two details at the most in each section.
As they work, I walk around and help, or model for students who need to see it again.