Ah, the happy, helpful colon. Use this little guy with lists, quotations, or to explain the thing (technical term: clause) that precedes the colon. So:
Things we need for camping: air mattress, tent, stove.
I love what Nietzsche said about perseverance: “You can never climb in vain: either you will reach a point higher up today, or you will be training your powers so that you will be able to climb higher tomorrow.”
Life in three words: anything is possible.
Cautions when using colon:
After the words “as follows” or “the following” or where those words are implied.
In formal salutations
Where dialog is used (but aren’t bracketed by quotations. Allen: People of mediocre ability sometimes achieve outstanding success because they don’t know when to quit. Most men succeed because they are determined to.)
Don’t use a colon after a verb. In other words, don’t do this: What I need: chocolate, punch… (though, I have to say as a side note, not really sure why we can’t do this…seems to make sense to me to list after the word “need” but what the heck do I know?)