Outlining is an excellent way to have students process what they have read.  For a 6th grade student, it would be most logical to have the outline match the number of paragraphs in the article that is under consideration.

Each main point line of the outline would then capture the topic of the paragraph -- perhaps it would be a rephrasing of the topic sentence. Then the sub-points of the outline would be any supporting details the student can summarize or infer from the body of the paragraph. Using a traditional outlining model it would look like this:

I.  Topic of Paragraph

A. Supporting detail or example

B. Supporting detail or example

II.  Topic of Paragraph #2

A.  Supporting detail or example

B.  Supporting detail or example

Etc.

This simple outline would be a manageable start for a 6th grade student to learn the essentials of the skill of outlining and more importantly the skill of learning to discern the essential information from what he or she is reading.  Outlining is a great way to engage the brain to process -- or "do something" with the sentences on the page.