C may also be for controversial, as I put forward the following theory.
I'm not being sexist, or making sweeping assumptions, I don't intend to offend anyone (ok, enough disclaimers, get on with it!) but it's been my experience that men are more concise than women. A gent may say "I went shopping for brown shoes yesterday, couldn't get any so I bought black instead", while a lady may go into detail about which shops she visited, which shoes she tried on, etc. Not a bad thing (the woman's version is obviously painting a fuller picture, telling a more detailed story), just one of the differences I've noticed between lads and lasses. I'm sure it can be the other way round, too.
So, where's this going? Well, one of my favourite books on writing is Strunk and White's The Elements of Style, recommended by Stephen King in his brilliant On Writing, which is my other favourite book. Not only does it tell you where an apostrophe should slip in and how to un-split infinitives (that's the crew of the Enterprise going boldy, then...), but it also has the best advice I've ever been given when it comes to writing and editing, all about being concise (which I originally intended to be with this post). That advice?
Omit needless words.