I find that students learn much more by correcting their own mistakes, using my proofreading symbols on their papers. Correcting assignments goes much faster for me, and the students have to think about their errors, without my "spoon-feeding" them the corrections, especially repetitious ones. The symbols can be used to remind even the lowest levels, with just the grammar rules they know so far (like spelling and capitals.) Naturally, the list is expanded to more symbols as students learn more rules--this is an abbreviated list. I couldn't show it here, but for the "change the order" symbol, just wrap it around the mistaken words.