If you see a lot of pesky red underlines while writing in most OS X apps, or you simply want to have more control when polishing your text, OS X’s Spelling and Grammar panel should come in handy.
OS X automatically checks spelling and grammar as you write in most apps, and you can adjust this behavior under Edit > Spelling and Grammar). When a word is underlined in red, you can right-click it to view any spelling recommendations, or you can tell OS X to learn the spelling of the word (for, say, your last name or a strange product name) or to ignore it entirely (if you’re typing babble or lolspeak).
You can also hit ⌘-⇧-: (Command-Shift-colon) to automatically select the first underlined word in your document and display OS X’s Spelling and Grammar panel. It’s a dashboard that gives you a sort of birds-eye view of spelling corrections and other options, including a “Find Next” button to help you breeze through your document.