The intended audience also plays a role. If you're quoting for an academic audience, you may need to be more formal and provide more background information. For example, when quoting from 'Moby - Dick' for a literature class, you could start with 'In Herman Melville's complex and profound 'Moby - Dick', which has long been studied for its exploration of human nature...'
The plot is an important element. You need to make sure your lead - in doesn't give away too much of the plot if it's a spoiler - sensitive quote. For instance, if you're quoting from a mystery novel like 'The Hound of the Baskervilles', you can't give away the solution to the mystery in the lead - in.
The tone of the novel matters. If it's a comical novel like 'The Hitchhiker's Guide to the Galaxy', your lead - in should have a light - hearted touch. You could start with 'In the zany and absurd universe of 'The Hitchhiker's Guide to the Galaxy'...'. This sets the right mood for the quote.