The first and most important rule of the interior decor is the combination of some elements with others, that is, "rhyme". Selecting different pictures, vases, cushions, etc., think about how they are combined with any object of the interior in color, shape or texture. For example, try to apply for curtains, sofa cushions and chairs or a very similar fabric or the same, but with different textures.
http://bord-eaux.com/the-most-import...or-decoration/ - here is an article with some tips.