As for the actual interior decorating, you can apply yet another concept in thinking up good ideas. Try to modify already thought up ideas. This can be in a form of semi-alteration of a concept, much like forming a different view or perspective to an already known concept, or trying to inject a little new concept to a current idea. The change in the idea should not bee too great however, and if it does become so then you might as well separate it from the original idea and treat it as another whole new separate idea.
For example, Victorian interior decorating features mostly 19th century style of architecture and interior design. You have the freedom to alter this design by adding, let’s say, articles of the same era but from a different part of the world, for instance, 19th century Russian art nouveau. Again, you have to pay attention to the combinations that you are going to plan, or if ever you are going for an entirely new style, try comparing it first to a current style or decorating technique to see if it fits the picture. But with careful planning and enough creativity, you can now create interior decorating styles that make it your own.