Every time I look up. To capture the near infinite level of detail of the real world you'd need to think pretty methodically. I'm a programmer by trade so I tend to split things into categories;
air, land and sea breaks down into
clouds, atmosphere, sun, celestial bodies
flats, hills and rocks and
oceans, lakes, rivers, ponds
then I'd break these down even further.
But that's only if you want to put a lot of effort into it, which if you want to recreate nature you'd have to. Planning ahead saves a lot of hair loss and constipation in the future