well.. i can't really show you well enough unless i actually own a PSP, but i could probably give you some tips:

1. Use lots of bubble wrap
2. Make sure the item doesn't move about inside the box/packaging
3. Make the package discreet (use brown paper). This is to avoid theft

i mean dun let people now whats inside la.. make sure can't see that its a psp.. even the.. coz there are cases where when the items are received, the contents have been changed.. look around the trade dispute and you'll know what i mean..