This gorgeous, hilly "village" neighborhood is, in my opinion, the most charming and my favorite…read morearea in Hamburg. It's known as the "stairs quarter" and is an upper class neighborhood that's part of the Blankenese quarter. There are hundreds of absolutely beautiful hillside homes, gardens, narrow streets, and gorgeous landscape views with the Elbe River in the background (and a beach). This is a must-do if you're in Hamburg.
You can access Blankenese station via the S1 in direction of Wedel (easiest mode of transport, takes around 20-25 minutes from central Hamburg) then walk 5-10 minutes to the neighborhood, or take Ferry 62 from Landungsbrücken to Finkenwerder then Ferry 64 to Teufelsbrück then bus line 36 to Blankenese (scenic route - recommended if you've never been on a longer ferry trip in Hamburg).
I'd absolutely recommend taking a day trip out here as you won't regret it! Just wander around on a sunny day and enjoy yourself! Make sure to hit the Süllberg hill which is 75m in height (there's a 5 star hotel and 2-Michelin star restaurant up there, as well).