Take your main character, or one you create, through a stream of consciousness. Write what would go through their mind in a five minute period. It doesn’t have to make sense.
Go outside. Stand in one spot. Turn slowly in a cirlce, taking in all the scenery around you. Then do the same thing but in the opposite direction. Now go back inside, or away from where you just were, and write down everything you just saw. Be as specific and descriptive as possible.