One thing I recommend is to add luxurious, elegant details. A personal favorite would be the doorknobs and drawer pulls available from Anthropologie. A doorknob or drawer pull is such an easy thing to switch out, and the designs available can really change the whole look of a room. Think about adding drawer pulls like this one to an all-white kitchen.
Curtain rods are relatively simple to upgrade, too. A surprising place to find an affordable, chic curtain rod? Home Depot.
Sew a bead or bauble onto a pillow, or even use an old brooch or pin to liven up the look of a curtain. Tiny accents can make a whole room sparkle, and the details will make it feel more like home.
It's just another easy way to make life more lux for cheap or free.