Steven Pinker is a brilliant linguist with an ear for the common tongue and a brain to understand how it fits into the new millennium. Still… there are words which he says we (the collective, English-speaking we, not you in particular) get wrong with alarming regularity. He also has a word or two (or ten, in fact) to say about modern grammar myths and issues which we all think are rules but in actuality are not.
Of course, for my money, you can’t go wrong with The Oatmeal when you need spelling advice.
Getting the Hang of Thursdays 
“every time you spell it this way, a dolphin gets run over by a jet ski”
So sad, really…