Do yourself a favour and follow Letters of Note on Twitter or just browse the site. It is full of great letters to and from great writers like, C.S. Lewis on Writing. Simple and very wise advice.
One of my favourites, because it reminds me of my dad Simon are the memos of Edward Mike Davis, owner of Tiger Oil Company.
Dad used to stick very similar memos on the door of us kids’ bedrooms. I can only imagine he sent the same memos around his office. Find all 22 of the famous Tiger Oil Memos here but below has to be one of my favourites. Apart from the aversion to alcohol, it is my dad in a previous life.
I love The Oatmeal. Great comics, great wit and excellent advice on grammar from artist Matthew Inman.
Combined with fantastic illustration, Matthew Inman does a better job than just the text explanations from my site.
You can order posters from The Oatmeal site, they are entertaining reminders that you should definitely put up in your writing room.