nalgene/small bottles

you may pack small items in nalgene. There are several ones that are very well built and pretty much waterproof. You can use small bottles to pack so that you don't have to carry big bottles with you. See through and clear nalgene/small bottles are preferable (they are easier for security purposes after August 2006)

Pack in Plastic

before packing them in your backpack, consider packing everything you have in clear plastic bags (preferably zip lock), divided by clothing type, e.g. underwear, shorts, t-shirts etc.. Each form of clothing in one nylon bag. All this is most useful in many ways: for instance, when unpacking your bag simply take out from the bag a few nylon bags and you can presently see piece of clothing that you were looking for. So an overnight stay simply means removing one piece of clothing out of your plastic bag - no rummaging. This makes being checked by customs plenty of more pleasant.