1) WORK WITH WHITE
Use a limited palette and lots of white. It will make your condo seem bigger than it really is. No clashing colours, no questionable accents, just completely spartan like you don't have anything resembling a personality that is HUMAN. Instead you mix textures... suede sofa, satin pillows, faux polar bear skin rug. The idea is to convince people you paid a fortune because you WANT people to think you're a rich snobbish douchebag.
2) GO SHINY
Anything stainless steel or high gloss ceramic white or black adds a sense of luxury to your condo. Do this enough and you will begin to feel like you live in an industrial warehouse instead of a home.
3) DON'T BUY A SHOWROOM SET
Avoid having all your furniture designs match. If all your decor looks like you bought it at Ikea on the same day your visitors will think you lack the skills to decorate. You're trying to show off like the rich douchebag you are so you have to the time to at least make it look like you put thought (or hired an interior decorator) into your layout.
4) SPEND A LOT ON ONE BIG ITEM
Spend all your wad on something really big and impressive. Max out your credit card by buying the most expensive 3D HDTV you can, with extra glasses for guests. Or if 3D HDTV isn't your thing, buy something equally expensive so you can show off to people.
5) BUY A PAINTING REPRODUCTION
You want to at least pretend you're sophisticated and know something about the artworld so go out and buy a really big reproduction of a famous painting, not something that is too distracting but is still pleasing to the eye. A really nice landscape, abstract painting or still-life... because you have no life and no time to go out and buy real painting from a real artist.
So obviously I am making fun of this. Interior designers these days are all loving the spartan white look and this look is being perpetuated by other interior designers on television and in magazines, etc. They have almost no imagination. Its a bit like the Nazis decorating... EVERYTHING MUST BE WHITE OR SPARTAN OR SHINY! *Best imitation of a German gestapo officer*
I say live a little. Want to impress people? Put real thought and personality into your decor. Use wood, mix palettes, experiment. Sure you can still buy big ticket items, but only if you really want them and not just because you're trying to impress people. BE YOURSELF. Don't try to present yourself as some bourgeosie spartan douchebag who must have everything looking perfect.