Back in my early days of learning how to write I used a lot of exclamation marks to show excitement, fear, anger, but a wise friend of mine told me to use action to show these emotions not punctuation.
I saw this on Raising Hope and thought it illustrated my point perfectly.
For those who don't watch the show, I'll set the scene. Jimmy is trying to get his daughter into a fancy preschool and on his application form has used a lot of exclamation marks.
I'm sure there's lots, but what's one thing you learned early on your road to becoming a writer.