To ship a package to an APO address, you pay the domestic shipping rate even though the package is going overseas. If you have a package that does not weigh a lot, use the domestic shipping rate. If you have a heavy package, its probably better to use the flat rate shipping boxes. For sending letters and cards, all you need is a regular postage stamp!
Christmas is just around the corner so remember that when shipping care packages they need to go out at least 6 weeks in advance so that they will arrive on time!
The United States Postal Service has special boxes for our military care packages. These are flat rate shipping boxes with a "We Support You" logo on them. These boxes are free and come in bundles of 10 or 25 and can be obtained at the United States Postal Service website.
For boxes, make sure the contents will not shift around. If you have extra space consider using old news papers, styrofoam peanuts, plastic bags or bubble wrap! Also make sure you do not forget the customs form. Make sure you write down all the contents in the box before taping it up!
If you send something small like a flash drive, tape it to something large or put it in something. This way if the box gets searched and its contents get removed it will not be lost. Objects that are small can easily be lost.
Pack everything in plastic baggies. It keeps things organized and if there are food items it will ensure they do not open them. Plus then your soldier will have extra baggies, which is another commonly requested item.