Semicolons ought to be one of the easiest punctuation marks to use correctly. For one thing, they’re not essential, so if you’re not sure how to use them, don’t. For another, they only have two uses anyway: as a sort of “super comma” for use in lists where the items themselves contain commas, and for linking two very closely related sentences into one without adding a conjunction. Just remember, if the two parts of the sentence couldn’t stand separately as complete sentences, don’t link them with a semicolon.
And here’s the big thing, the thing that triggered this particular rant: Semicolons are NOT interchangeable with colons. NEVER use a semicolon before a list.
Incorrect: I had a really big breakfast; bacon, eggs, pancakes, toast, and orange juice.
Correct: I had a really big breakfast: bacon, eggs, pancakes, toast, and orange juice.
For further reading, The Oatmeal has a funny and easy-to-understand infographic on how to use semicolons.
