Painting a little square of colour on your wall is a good way to test out potential wall colourings, but you only get to see how it looks on that particular patch of wall in that particular lighting situation. To see how it would look in any part of the room, paint a piece of poster board and move it around. Photo by Doug Waldron.
This idea from Food 52 is super clever. Not only does it let you see how a colour and finish looks in every single corner of a room, it saves you the trouble of having to go back and cover up colours that didn't make the cut. You can also test out a whole bunch of samples at once, and move them from room to room if need be, making sure you pick the perfect shade for every wall in your home.