Take lots of pictures.
If the outside of the package is damaged, it is the carrier's issue. If you have insurance, then the seller needs to work with you for the insurance claim. (i.e. providing receipts).
If the seller is 100% at fault then the pictures will reveal the issue. Sometimes the seller will ask you to send it back (just to get your goat).
I had one seller where I sent packing and shipping instructions. They got mad at me for "telling" them how to pack it and subsequently did it wrong on purpose. The lamp came sqaushed. I provided lots of pictures on a web page where I archived bad sellers and pictures of them. They forced me to send back the package at my expense. but they begrudgingly refunded me.
They had no case, because I sent them very clear detailed instructions on how to pack/ship. They complained on eBay's mail system so they could not dispute the issue.
Some sellers may see the instructions, then charge you more. I had one seller charge me $20 more because they did not get the price they wanted. For the $20 they ended up with bad feedback both for overcharging me and shipping the lamp 60 days later.
Most sellers will work with you. The key is to provide really good packing instructions and examples. Most sellers will try.
I myself bought something off eBay and I did not specify packing instructions but it did come damaged. Now because it came damaged am I stuck with it? Do I ask for a partial refund or just ask for a full refund and return the items? I have opened a claim just in case. This is not my only purchase that is damaged at the moment and I will have to open another claim.
My question is this, my item arrived broken and I don't feel like I have to buy a broken item that wasn't packed well which is why it got damaged. If the item was insured it wouldn't be a problem but it wasn't. So is it the sellers responsibility to ensure the item arrives safe?
It is the sellers responsibility to provide safe packaging.
This is where your pictures provide the details. Consider your self as a mini lawyer proving a case of responsibility.
You don't have to accept a broken item if the seller's packaging was inadequate. The seller may feel they took all kinds of precautions, but some really do not understand the traveling issues with lava lamps.
In the future it's up to you to provide instructions and to request insurance. Otherwise they will always be coming broken.
In my situation the first few packages came broken, after I provide instruictions and requested USPS priority or UPS ground, the frequency of broken items dropped greatly. The only items that arrived broken after that were from sheer negligence.
Pictures of packaging are key.