Good writing newer goes out of style. In fact, students are writing a lot more than students did ten years ago because of all the blogging and instant messaging. Of course, one can argue that the writing in these forms is not very good, but at least students understand the importance of writing. Ten years ago a student might have thought that the telephone had replaced the need for written communication, but I'm sure that far few students would now make that claim.
The Chicago Manual of Style is the bible for correct writing. There are few parts of the online system, but you'll have to pay if you want to use the full system. This may be a good investment for the school library's computer.