I was hoping to find one quick tip, and instead found this list of 7 useful ideas.
The list is nice because you can pick what works for your organizational style. For example, the 6th tip — keep a separate basket for clean, lonely socks — sounds like what I do now, which doesn't work for me. But the tip to buy fewer types of socks sounds pretty great, especially when it comes to dress socks.
See the full list at Home Your Way.