The overall structure first
Explanation: First look at the overall structure ie a introdutory, body, and concluding paragraph. Then you should revise the paragraph looking at sentences and words.
During the revising stage of the writing process, the first thing to revise is to revise:
the overall structure of your writing
Revision of any written text is the process in which the writing is reviewed, edited and altered. The structure of the text is considered at the first level of revision. The thesis statement is also reconsidered and revised so that it can lay out the important points of the text.
I would say individual sentences.