The House as Character
The haunted house needs to be as fully realized as any character in your novel. Give it a personality: is it malevolent and active, or sorrowful and passive, or so deeply damaged that it can't help what it does? Give it desires: what does the house want from its occupants? Give it a history: what happened here, and what does it remember? Map it physically with enough detail that readers could navigate it. The house should feel like a specific place with a specific nature, not a generic gothic backdrop.