Loosen your strings down all the way to remove the tension from the guitar. Remove the strap peg from the end of the guitar if it isn't glued in. It doesn't take much of a hit to split your guitar there. Put crumpled up newspaper or something around the headstock and neck area for support. A guitar's neck can break, (get whiplash), from rough handling even in the case.
Guitars with hard shell cases can be shipped safely without boxing but if your hard shell case is like one of mine, the finish chips or tears off pretty easy just putting it in the car and stuff so I would protect it anyway. Put it in a cardboard shipping carton. If you have trouble finding one, try to get one that a
local music store is throwing away from a shipment of guitars that just came in. Add crushed newspaper, padding, etc. around all the surfaces of the case. If you only have a soft shell case, add a piece of plywood to the inside of the carton over the top and bottom of the case. Use fiberglass strapping tape to strap it all up good and tight.
