Deep work is less about heroic concentration and more about removing avoidable friction.
Choose one important task before the session starts. Put the phone away, close unrelated tabs and define what 'done' means. A 45-minute block with a clear finish line can be more valuable than three hours of fragmented attention.
When the session ends, write down the next action. This makes it easier to restart later and prevents unfinished work from occupying your mind.