Packing a bike in a box is just a lot of common sense. Wrap, box, protect like you would any other packaged item you send in the mail.
Go to a local bije shop and ask to see a new bike unpacked from a box. You will get some ideas, and maybe get the packing material you need as well.
I have recieved a few bikes sent to me from ebay buys. Most came with minimal packaging. One came from Poland as simply a frame in a box. They all survived.