Letting in the light: I prefer everything on dimmers so one can read when one wants but then lower the lights for parties. Avoid overhead lights or anything that shines in one's eyes. Lighting stores are tricky because whether they are high-end or low-end they all are filled with horrible designs. In lighting, as with many things, the simple choices are what will often do the trick. In general, the more decorative, the more I run screaming in the other direction.
Covering flaws: Every apartment has an architectural faux pas or two, mostly caused by items we need: pipes, radiators, poorly placed windows and doors. Sometimes a well-placed folding screen can do wonders to help mask those offending elements. In this case, the air conditioner-radiator under the window was a hideous but highlighted feature in the room. The tin-can screen turns it into a work of art.
Playing with color: New York requires color because the light in the city is so gray. My favorite paint is Benjamin Moore. I always, always buy quarts of the colors I think I want to use. Then I slap samples on the walls before making the final choice. I'm often surprised by how I respond to my selections.
Rugs: Nothing pulls together a room like the right rug. In oddly proportioned rooms, this often means something custom -- a simple bound carpet or sisal matting can be a great affordable choice; any good carpeting store can do that for you. I also love needlepoint and Tibetan-style rugs, depending on the application. The mistake I see so often is that the rug is too small -- little patches of rugs often make small spaces seem smaller. In general I prefer sixteen-to-eighteen inches of the floor to show around the room. This lets you know it's not wall-to-wall, but still pulls the room together.
Antiques stores: For classic small pieces, I like Hoffman Gampetro Antiques (1050 Second Avenue; 212-758-1252). I also do a lot of shopping at Christie's -- getting the catalogs is my great luxury. I love shopping without leaving home.
Chain stores: Crate & Barrel, Pier 1, Ikea -- they all do a great job, but I buy one or two items and get out. I don't want to buy someone else's overall aesthetic. We went to Fishs Eddy on Broadway and 77th one day and bought dishes and glassware and cheap silverware and stuff. Jorge came to New York with literally two suitcases.