The topic sentence, your main point, should be written in black. By the second sentence, however, you can start building your argument and writing in blue. "Red ink shall be used for quotations or other very specific evidence." Your reader needs an explanation for why that quotation is there and why it helps support your point. When you write in blue, that's when you add your thoughts and ideas to help explain your argument. "Another quotation will develop proof; use red ink again." Return to blue as you present more clarification or want to show ideas to defend your argument. Two blue sentences in a row are sometimes necessary in order to fully show your thinking, but you shouldn't have two red sentences in a row because you'll need to explain each piece of evidence you write about (and that means writing in blue). "Your responsibility as a writer is, of course, to provide a clear argument that presents your reasoning for all your readers to see and understand." Add as many more blue sentences "or red ones as you need" in order to provide the necessary evidence to convince your reader that you are right. Just be sure to explain each of your pieces of evidence so that your readers can see why you've included that quotation. Now that you're done explaining, come back to black for your conclusion.
D-10 is a messy room. Empty boxes sit in the corners, attracting dust and cockroaches. The empty boxes easily fill with garbage and clutter the floor. Dust and cockroaches make the room feel similar to a trash can at times. Magazines and books are thrown randomly onto bookshelves. A classroom library should be organized and easy to search. However, the library in D-10 is without any concern given to order and it's difficult to find the same books from day to day. Stacked in the back of the room, computers pile on top of each other, some not even turning on and several keyboards missing keys. Since the broken computers act more like paperweights than anything else, they just take up space without adding anything worthwhile to the class. Essentially, the computers are even more trash in the corners of the room. With trash, cockroaches, disorganized books, and nonfunctioning computers, D-10 is an incredibly messy room.
[Look back at all those red sentences. They are all physical descriptions of the room D-10, evidence that shows how messy the room is. But it's not enough to say that the room is filled with boxes or disorganized books or broken computers. A writer can't leave it to readers to make sense of that information because some reader out there might not make the same connection that the writer does. It's the writer's job to explain thoughts completely. Pointing out facts or evidence is important, but a writer also needs to explain to the readers how that evidence supports the main point. That's where the blue sentences come in, describing why the boxes, books, and computers mean that the room is messy.]