Be wrong fast.
For new features, you're going to get it wrong. The wrong UI, wrong flow, wrong value prop.
You won't know until you ship it.
So ship insanely fast. Get from whiteboard scribbling to ugly version within a week, day, or hour if possible.
If you can't ship fast, ask users: "Got this idea, want to try it?" If no one replies, question what you're doing.