Some quick tips on mailing holiday packages:
Check the last date a package can be mailed and still reach its’ destination before the holiday —Holiday Shipping Dates
Be aware of restrictions on what can be mailed and recommended packing of liquids. Mailing restrictions.
Buy boxes from the post office or choose a heavy box. If re-using a box, take a permanent marker and blacken out all labels.
Choose a box big enough to allow for cushioning materials–newspaper, shredded paper or foam peanuts
Shake your box. If you hear rattling, add more cushioning material.
Include the address and return address inside your package.
Reinforce all seams and tape the opening of the box close with 2 inch clear packing tape.
Do not use–string, twine or masking tape on your package.
Type or print your address so it can be seen from an arm lengths away. Do not use commas or periods.
Place a piece of clear packing tape over the address.
Include your return address in the upper left corner.
Sign up at USPS and print your labels using their services.