Lots of useful tips and tricks!
An example ?
Place some pieces of your clothing in your traveling partner's suitcase.
A suitcase gets lost so easily when traveling by plane. If you're traveling as a couple, slip some clothes into each other's suitcase and vice versa. If you lose a suitcase, you will be in much less trouble. If you are alone, you might want to keep a spare set with you in your bag or in the cabin.
Here is a selection of sites:
The 100 best travel tips
50 tips for packing your suitcase
I particularly liked suggestions 18, 24 and 48.