Carry a notebook.
That brilliant idea you KNOW you can’t forget? You won’t remember it five minutes from now. Also, carrying a notebook forms good habits of observation. You’ll feel very stupid carrying around an empty notebook, so you’ll start looking around for things to write in it. Once you start looking around, you’ll start seeing things… and spoiler alert, but the world is well worth seeing.
Don’t just record facts though. ‘Saw white fisherman’s shed with ramshackle blue-tile roof’. Describe how it makes you feel; the aura of it. ‘Salt-white fisherman’s shed with a blue-tile roof that drooped like sad, patient eyes, as though it were a weary lover watching the tide tease the shore in front of it but never come farther than the rocks.’
It will teach you to see the extraordinary in the ordinary things around you, which is the truest mark of a truly wise writer.