Commas are the biggest problem I find in editing. Here are a few more tips to learn how to use them properly.
"Meow," said the cat purring.
Should be:
"Meow," said the cat, purring.
If you have an action separate from the statement, then there should be a comma.
Another example:
Incorrect:
"I hate dogs!" screamed the cat jumping on the table to escape the pup.
Correct:
"I hate dogs!" screamed the cat, jumping on the table to escape the pup.
Sometimes you don't need a comma.
Incorrect:
"I want to eat a bird," said the cat, as he licked his chops.
Correct:
"I want to eat a bird," said the cat as he licked his chops.
Here his action smoothly moves along without the comma.
