Number one: Layer! Less to pack!
Two: Buy your shampoo, toothbrush and deodorant down there. They have little travel sized bottles in every convenience store. Less to pack!
Three: Mail stuff back home! Use the flat rate boxes to mail your souvenirs and extra clothes back home! Less to pack!
Four: drink to calm your nerves. Turbulence is a bitch.
Five: pack your phone or iPod with your favorite jams and have a movie or two downloaded on your phone!
Six: the little mini shots at the dollar store are cheaper and you can drink them while you're waiting to check into your flight.
Seven: travel with aomeone. It's safter.