The most prominent narrative technique in Wuthering Heights is Emily Bronte's complex use of narrative structure and narration. A more standard telling of the story would follow Heathcliff's history from his arrival at Wuthering Heights until his death years later. Even the use of a frame narrative is not in and of itself radical: Bronte could have simply had Nelly tell the story to Lockwood and have left it at that. Instead, Bronte intersperses several narrators throughout the story, even going as far as to have narrations within narrations.
For example, much of the story is told by Nelly Dean, but even her narration is being written down by Lockwood, who is the initial narrator and viewpoint character. And while Nelly's narration provides the bulk of the story, Lockwood also finds Catherine's diary entries the night he stays in her old bedroom at Wuthering Heights, providing direct insight into a part of Catherine and Heathcliff's childhood experience that Nelly would not have been aware of. Nelly also shares the contents of a letter Isabella wrote to her after marrying Heathcliff, giving the reader additional information of which Nelly alone would not have been aware.
While this unique narration style has inspired much praise on a technical level, the book's narrative structure also works well on a storytelling level. By introducing the characters and settings of both Wuthering Heights and Thrushcross Grange through Lockwood's eyes in 1801, Bronte is making the reader curious. The reader might ask why everyone at the Heights is so miserable or what makes Heathcliff so powerful and cruel.
The novel also makes good use of foreshadowing, especially within Nelly's narration. For example, in her hunger-induced delirium, Catherine cries that
they may bury me twelve feet deep, and throw the church down over me, but I won't rest till you [Heathcliff] are with me!
This prefigures her ghost's haunting Heathcliff in the years after her death.
Nelly also foreshadows events directly in her narration, such as when little Cathy is born and everyone is too upset over Catherine's death to attend to the new baby:
An unwelcomed infant it was, poor thing! It might have wailed out of life, and nobody cared a morsel, during those first hours of existence. We redeemed the neglect afterwards; but its beginning was as friendless as its end is likely to be.
Nelly is looking back on this past event with knowledge of what will happen years down the line. The ominous last lines prefigure Cathy's miserable forced marriage to Linton and her current imprisonment at Wuthering Heights.
All of these techniques blend together to complement one of the novel's major themes: how the past is never past, but always affecting and sometimes even blending with the present.