How To Indicate Unspoken And Indirect Discourse

What type of markers or emphasis should a writer give to signal that a character's thoughts are unspoken? Though some people disagree, the consensus is that they should be enclosed in quotation marks as if they were said aloud:

1. "She surveyed the shambles of her room and thought, 'Where do I start?'"

This mode of what is known as unspoken discourse assumes that internally vocalized thoughts are a form of direct speech. "Unspoken discourse" is not to be confused with "indirect discourse," which describes indirect speech, or paraphrase:

2. "She surveyed the shambles of her room and wondered, where should she start?"

In this case, the person would not think, "Where should she start?" in those words, so the final phrase of the sentence is a paraphrase, not a quote, and should not be enclosed in quotation marks.

Indirect discourse has another, similar form:

3. "She surveyed the shambles of her room and wondered where she should start."

Notice that in this example, a different type of paraphrase, a comma does not precede the thought, and no question mark punctuates this sentence, because it's not a question.

As I mentioned above, some writers prefer to omit quotation marks in unspoken discourse:

4. "She surveyed the shambles of her room and thought, Where do I start?"

This style is also correct, but it requires greater attention from the reader, and it seems more trouble than it's worth to distinguish between spoken thoughts and unspoken ones, especially in fiction.

Employing italics is an alternative strategy for unspoken discourse, but this method is best used in internal dialogue, when a person is conversing with their alter ego, or with a disembodied entity such as a spirit, or perhaps a guiding force from within:

"The voice seemed to resonate inside her: Go forth, and fear not."

Thanks to Mark Nichol / Daily Writing Tips
http://www.dailywritingtips.com/how-to-indicate-unspoken-and-indirect-discourse/