It’s not necessary to use rather expensive materials so that the luxury impression was reached.
Almost all the interiors have something in common: glossy, most usually copper / brass surfaces and achromatic colours (black, grey, white). If you use those elements you’ll immediately create more luxurious mood. Of course, marble is already considered as a mark of a good interior and it contributes to a luxury impression.
Now you’ll surely find a glossy metal vase or plates in a frequent accessory shop, therefore, you’ll bring exclusive charm for your interior by very cheap means. Of course, the things shining like gold will not fit anywhere – you need to feel interior and understand if it lacks any detail or not. Or to refer to the experts of that sphere.