When analysing structure, think about how Stevenson has ordered his text and put it together on several levels:
Dr Jekyll and Mr Hyde is split into ten chapters and Stevenson has given each chapter a title.
Stevenson has created chapter titles to summarise the chapter's content, making it easier for the reader to navigate the text. From looking at the chapter titles, you can see how tension peaks during chapters 4-8 and then lessens from chapter 9 onwards as the narrative is resolved.
Why does Stevenson create tension in chapters 4-8, the middle of his narrative?
At sentence level you should consider how an author has created a sentence and to what purpose.
Below is an example section from the text. In this section, Dr Lanyon is describing the shock he's had - not mentioning anything about Dr Jekyll and his experiment.
"I have had a shock," he said, "and I shall never recover. It is question of weeks. Well, life has been pleasant; I liked it; yes, sir, I used to like it."
Here’s how to break down and analyse this quotation, thinking about the sentence lengths, sentence types, sentence order and the punctuation used.
"I have had a shock,' (1) he said, (2) 'and I shall never recover. (3) It is a question of weeks. (4) Well, life has been pleasant; I (5) liked it; yes, sir, I used to like it."