On the March cruise to the Caribbean I noticed that Craig's cousin's children had all their clothes separated into days by Ziploc bags. I have done this before on a camping trip when I thought it would rain and obviously this would be difficult for people who are adult sized. I could maybe get one pair of jeans in one of those bags!
However, there are adult versions of this idea. They are called Packing Cubes and I love love love them! I have like 5 so far and plan to get more for my coming trips.
Here's a link to show what they look like. Cool Colors too!!