Day 180: Use an exclamation mark only after the interjection, not after the statement.

If you want to start a statement with an interjection, and if you want to use exclamation marks to create emphasis, only use the exclamation mark after the interjection. The interjection carries the emphasis, not the statement. This isn’t really about right and wrong. It’s a style issue that separates amateur and professional writers.

Amateur: “Hey! Watch where you’re going!”
Professional: “Hey! Watch where you’re going.”

Amateur: “Cool it! You’re going to get us in trouble!”
Professional: “Cool it! You’re going to get us in trouble.”