Short of vacuum sealing your clothes, there's no better way to make the most of your suitcase than being well organized. Some of us do this naturally, while others can use a little assistance. For the latter Flight 001 has introduced the Spacepak Line of 6 bags to go in your bags.
I flew to LA yesterday and used the Clothes Pak and the Shoe Pak inside my rolling carry-on. In addition to fulfilling their promise of maximizing space, they kept everything nice and neat. The clothes pack has two sides to it-- you start by packing the clean side and as the trip goes on, dirty stuff gets put in the dirty side. Simple and smart.