I think symmetry, a lack of clutter and statement pieces make luxury. I have two really big oversized table lamps on either side of a consol unit. But nothing else on it - which I think looks great, but is clearly a matter of taste! Big oversized poof, mix and match duck feather cushions (duck feather cushions you sink into are just yum - I hate the feel of polyester filling, nothing comfortable about it!). And good curtains, that either exactly fit or are luxuriously pooled with weights on the floor.
I'm sure someone else will be along to say that the above is their idea of linda barker hell!!