Sometimes it is useful to break up blocks of your writing visually with comment boxes. I use these to separate out major sections of e.g. a piece of code. To do this, highlight the lines of text that you want to enclose in a comment box, and then use M-x comment-box .

The example below illustrates this, with the first comment box showing the default behaviour. I prefer a wider comment box, as in the second box below.

To get the boxes in the second example, add the flowing code to your emacs config file (copied from irreal). This defines a function that you can run with M-x bjm-comment-box and sets up a keyboard short-cut C-c b b .