What narrative techniques does Dickens use in Oliver Twist?
Oliver Twist is what's known as a progress. In fact, the subtitle was "A Parish Boy's Progress" originally. In a progress, the main character does not take action directly. In short, he does not make things happen, things happen to him. Oliver does not grow or change as a character, and he does not make choices. This is an interesting choice for a main character, but consider it historically. Oliver Twist was the first novel with a child as a main character. Dickens was interested in A Pilgrim's Progress and wanted to mimick the model. He was a young writer then, and had never written a full-length novel. His first published book was The Pickwick Papers, which is really a collection of humorous sketches.
It's important to note that this was Dickens's first attempt at outward social commentary aimed for reform. He was successful, a fact incredible in itself. By humanizing Oliver, the Poor Law became an atrocity that eventually England couldn't stomach.