How should I decorate my new apartment?I like the idea of Feng Shui
I don't know what color your current furnishings are, but if you want to add a color scheme that is complementary with Feng Shui, try to balance colors.
Red equals fire, and needs to be balanced with beige (earth), white (metal), blue (water), and brown/green (wood). My suggestion is to choose a central color (it might be white in your case as you aren't painting) and add the other colors are complements.
If you have a beige, blue, or brown couch, you can add red throw pillows or just one red throw pillow among a few neutral. You can also add the fire element by putting art work on your wall with red as a central theme.
The wood element can come into play with plants, such as bamboo or ferns. Water can be balanced by adding a fountain in the corner that will provide a soothing trickle like rain on your roof top.
You can find some great area rugs that will add color and dimension to your room. Try a rug such as this Red Shag or this blue that adds beige/blue components.
I'm not up on specific placements for your elements, but this should help for a start.