What is the proper way to write a thought in a story?

Answer 1

Do it in italics, I do in my stories:

For example: I heard a gun shoot from somewhere. Great, I though, I knew I shouldn't have let Dean interfere with this, he's just a kid...

Ect, Ect.

Answer 2

Most writers just write something like "He thought _____" or "Her thoughts were about _____."

Sometimes you'll see a thought written out as if it were a dialogue, such as "I wish I were in Hawaii," he thought.

Rarely, you might see the thoughts written in italics. I can't believe she just said that. Todd smiled at his wife and then, when her back was turned, made a face.