I just read this blog post after seeing it on Pinterest. I think it is a great description of how to pack lightly -- even when travelling for months at a time.
I'd add that I LOVE my packing cubes which can be found here. They have allowed me to keep things neat and easily accessible when living out of a backpacking backpack for several months. Really, they're wonderful. Here's a picture:
I also should admit that I did not pack light for this trip... and although it's somewhat nice to have more things here, it might be nicer to live lean especially when you're not really in your own space.