M is for making every word count which is exactly what it sounds like. It is making sure that when you are writing you make every single word carry its own weight and not fill each page with filler text in an attempt to draw out a moment any longer than it should be. If you have a tendency to idly type to get the creative juices going before really digging into a scene, that's great! Just make sure you go back over those idly typed scenes to clean up any extra lines that slow the momentum of the story.
On the plus side, doing away with unnecessary filler text will lower your word count and, if you are seeking to have a novel published or represented by an agent, a lower word count may give it a better chance. Although I hadn't known this initially, the chances are greater that an agent will pass over a novel by a first time writer that is over ~110,000 words.
References on word length:
"How Long Should Your Story Be?" by Lee Masterson, Fiction Factor
"Novel Word Count" by Nathan Bransford, Nathan Bransford
(If you have any questions or constructive critiques, feel free to leave a comment down below. You can also follow me on Twitter @TheWritersExpt.)