Be honest. The characters may lie, but the writing cannot. The scene may be deceptive but the context must be real. Even if the character is dreaming or psychotic or hallucinating, it must be real. Don't think of purple cows. See? Everyone thinks of purple cows until the next image or sense is alerted. What next?
A purple cow smells of grapes. The cowpat drops with a splat like shredded gummy eggplant, fried and lost in the back of the fridge growing a sauce of furry violet mold rich and sickly sweet like prunes decaying.
Got sight, smell, taste, touch and sound there. Talk about your purple prose, but I forgive me, it's an illustration.
Highland cattle watch from the rocky hillsides in Scotland, their shaggy coats the color of cinnamon and nutmeg. They're wilder than their two-tone American cousins. Those black and white coats even adorn computer boxes but the Highland cattle disdain advertising. They wait for winter, cropping the short sour grass, ignoring the purple heather.
Now purple is in the backrow, a sidebar, a decorative touch.
What's another secret of writing? Read what you like and what you don't like. Why? Because there are different ways of looking at the elephant, as the Indian fable goes.
Six blind men come upon an elephant, each touches a different part. The man at the leg says the elephant is like a tree. The one touching the trunk says the elephant is like a snake. The one holding the tail says the elephant is like a rope. The one at the side says the elephant is like a house. The one touching the ear says the elephant is like a fan. The last pricking his finger on the tusk says the elephant is like a spear. They are all right as far as each goes, but the elephant is much more.
Writing is giving more than what meets the eye or hand.