A few favorite concert halls where the acoustic is amazing: Suntory Hall (Tokyo), Koerner Hall (Toronto), Weiwuying (Kaohsiung), Walt Disney (LA), Davies (SF), Elbphilharmonie (Hamburg), Musikverein (Vienna), Concertgebouw (Amsterdam),

When I'm performing, I usually think of characters/personas. Sometimes it can become a story but usually it's simply a conversation or scene that happens. For example, at the bridge passage of Mendelssohn's 3rd movement, I imagine a conversation between a young student and an old teacher. The young student keeps asking why while the old teacher just keeps shaking their head. Eventually the student becomes determined to make their own decisions and that's when the 3rd movement starts into this adventure with lots of valleys, mountains, and beautiful scenery just rushing past.

If your mind is blank (which it can very easily become when practicing by yourself), then what comes out will also be blank and robotic. This is why it's important to always have a focused and conscious state when you're practicing.