tl;dr:Tom recommends several strategies to mitigate the negative impact of smartphones on attention span: (1) Conscious reduction of smartphone use. (2) Engaging in long-form content, such as books, podcasts, and articles. (3) Creating "phone-free" zones and times e.g. before bed or when you wake up. (4) Awareness of when you reach for your phone to fill time. (5) Experimenting with reduced usage.