So there you are - leaving the flooring store, the paint store, or the fabric store, and your arms are laden with different samples. Now what? Now you take them home and observe them! Put that flooring sample on the floor in the room for which it's intended. Tape a paint sample to the wall that will be painted. Drape the fabric over the sofa that will be recovered. Look at it, then go away. Come back in a few hours and look again. See it in the morning, mid-day, dusk and evening. What looks good at mid-day, may look washed out in the morning. what looks like a glowing orange at dusk, may look more red at noon. There's science behind it, wave lengths and such, but all you really need to know is how it looks. Once you've observed in all the different lights (and maybe jotted down a note or two) then you can make your selections with confidence!
If you're interested in the science, this article by Tad Simons at STIR breaks it down for you: