One approach is to make typo/grammar annotations only on the first page, or paragraph. Then add a clear note saying that you will only comment on the "big thin

One approach is to make typo/grammar annotations only on the first page, or paragraph. Then add a clear note saying that you will only comment on the "big things" later in the document. This avoid demoralizing the author, while still sending a clear signal that something is wrong. If you make detailed comments the whole way through, you run the risk of encouraging the writer to submit sloppy first drafts. Unless it's your job to be the writer's servant, think carefully before taking on that role.