Know these words. Use them properly. That way, your smart friends will embrace you and your less-than-smart friends will look up to you and ask you things. And who doesn't like to be asked things?
Scot, Scots, Scottish. A native of Scotland is a Scot. The people there are Scots, not the Scotch. Scotch is something to drink and enjoy - and the older, the better. Somebody or something is Scottish.
whiskey, whisky. Use the -key ending for the Irish and Kentucky versions; use the -ky ending for the Scottish version.
premier, premiere. The first showing of, say, a movie is the premiere. When describing something as the first or best of its kind, use the adjective premier. Of course, premier is also a noun, being the title for the individuals who lead the provincial governments in Canada and Australia, or another word for prime minister in some contexts.
oral, verbal. Use oral to refer to spoken words: He gave an oral promise. Use verbal to compare words with some other form of communication: His tears revealed the sentiments that his poor verbal skills could not express.
noisome, noisy. Noisome means offensive, noxious. Noisy means clamorous.
memento, momento. A memento is something that serves to warn or remind. Momento is not a word.
mnemonic. A mnemonic (don't pronounce the first m) is a device to trigger one's memory. And don't pronounce as the non-existent newmonic.
May Day, mayday. May Day is May 1, often observed as a festive or political holiday; mayday is the international distress signal, from the French m'aider, meaning "help me."
Kriss Kringle. Not Kris.
Jamaica rum. Not Jamaican rum.
in, into. In indicates location: He was in the boat. Into indicates motion: She climbed into the boat.
hangar, hanger. A hangar is a building, usually for storing aircraft. A hanger is used to hold clothes.
door to door, door-to-door. Hyphenate when used as a compound modifier: He is a door-to-door-salesman. But: He went from door to door selling proofreading services.
Source: The Associated Press Stylebook and Briefing on Media Law, 2009.