As with a movie, word and image develop together, interdependently. Writing, like drawing, football or playing an instrument, is a skill and has to be constantly practised. Keep diaries, make storyboards, strip cartoons, write down observations. Never be put off if something doesn't come out right. Put it on one side and try something else.
Good writers are always good readers.
Store away ideas, keep your ears flapping on the bus, and a sharp eye for interesting incidents. Having terrific laughs with members of my family. Sitting under a tree in a sunny Italian landscape with a sketchbook and a glass of wine. Being in my workroom. Playing with grandchildren.