No! he yelled. Do it now! What on earth are you doing! Stop!
When used in a quote, exclamation marks should be inside the quotation marks:
Mary said, “I like chocolate a lot!”
Do not add a full stop after a sentence that ends with the an exclamation mark. The exclamation mark will be suffice to end the sentence.
Do not add a space before an exclamation mark.
I’ve asked you not to sing la Marseillaise!
Avoid using multiple exclamation marks:
The exclamation mark has a clear role inside the English language. Increasing the number of exclamation or question marks at the end of a sentence might appear to increase the overall emphasis, but in reality it just makes your text ugly and informal. One is enough to convey your feelings in conventional English.
It’s 8.30am and time I had a coffee break!
It’s 8.30am and time I had a coffee break!!!