Reading a sample board
A sample board is the working tool of any decorating scheme, and it is more useful than any amount of description. The purpose is not to present a finished idea but to test one: to put the materials that will actually be in the room next to each other, at something like their real proportions, and see what happens.
Proportion is the part most often got wrong. If a room will be four-fifths a single wall colour, that colour should occupy four-fifths of the board, not one square among a dozen equal squares. A board of equal chips will always look busier and more balanced than the room it describes, and it will hide the fact that one colour is about to dominate everything.
Light is the second variable. Colours and finishes should be judged in the light of the room they are for, at more than one hour of the day, and under the lamps that will actually be used after dark. A finish chosen under a shop light or a north-facing studio window has been chosen in a light that does not exist in the finished room.
Keep the samples large and keep them loose. A hand-sized piece of cloth tells almost nothing about how a pattern will read across a curtain, and a fixed board cannot be carried to the window or held against the skirting. Large samples that can be moved answer questions that a neat pinned board cannot.
Finally, leave the board in the room for a week before deciding anything. Almost every scheme that fails does so because a decision was made quickly in good light, and almost every scheme that holds together was looked at repeatedly, in bad light, until nothing on it was surprising any more.