Practicing system design out loud alone in my car turned out to be more useful than any article I read

Read a handful of system design articles and felt like I understood the concepts fine until an actual mock interview exposed how little of it I could produce out loud under time pressure. Started narrating my own practice designs out loud during the commute, no whiteboard, just talking through a notification system or a URL shortener like there was someone listening. Felt ridiculous the first few times. By the third week I could actually get through a full design without the long pauses where I used to just stare at nothing.