They tend to give the illusion of open space. When using a patterned wallpaper, if the room is small use a small pattern. If the room is large, you can use a large pattern. Decide on a focal point and decorate around it. Your focal point could be a piece of furniture, a fireplace, ect.
Pale pinks are serene and comforting.
The closer pink gets to red, the more energetic it becomes. Light colored walls and ceilings will make the room appear larger. The opposite for dark colors. When selecting a solid carpet color, choose a shade of your upholstery or drapery fabric to add interest. Don't choose the exact color, it will be to rigid.