In fiction, interior monologue is the thoughts of the character put into words, usually interspersed with that character's dialogue. It gives the reader an insight into what the character is thinking—which is often the opposite of what is actually being said. When you run across internal monologue used effectively in a book you are reading, study the technique closely and practice creating it until it works naturally and smoothly in your own writing. Interior monologue is always set off in a separate paragraph, the same as dialogue. It is usually printed in italics (underline it in your manuscript and the publisher will convert it to italics). Since each scene will be in the point of view of a single character, you don't have to indicate who is doing the thinking. The italics will indicate that it's that character's thoughts. For practical help on using internal monologue in your writing, go to: http://www.advancedfictionwriting.com/blog/2012/04/18/how-to-do-interior-monologue-in-fiction-writing.