Overuse of exclamation marks dulls their effect. Do not use more than one exclamation mark at the end of a sentence.
The film's last scene poignantly showed that his battle had been for nothing, and he had lost her and his dream forever.
NOT The film's last scene was so poignant! You knew he'd lost her forever! His dream was dead!!
Also, avoid using an exclamation mark in parentheses to indicate sarcasm or irony. Instead, rely on vivid language to communicate the desired meaning.
Mom was convinced that Marie's self‐confidence problem could be solved with a new dress, and she refused to discuss the issue further.
NOT Mom thought that Marie's self‐confidence problem could be solved with a new dress ( !), and she didn't want to discuss the issue further.