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Packing Advice
Carrier bags and newspaper make excellent substitues for bubble wrap
Always write a return address on the package, along with the buyer's address
If not sending recorded, take a photo of the senders address on the packet and ask for a 'proof of postage' at the post office
Don't accept the excuse 'must have got lost in the post' especially for UK packages, despite what everyone says, the Royal Mail are blooody good.
Selling Adivce
Be honest. That's the one way to stop anything coming back your way, list scratches, dent, imperfections, discolourations - it may reduce the end selling price by a few percent, but you won't have to pay for and accept returns due to mis-listing the item
If you home is pet and smoke free, let people know
If an item is heavy, offer to let people pick-up, or if you want to make a little turn, offer to deliver for say £1 a mile (one-way) and you can sell off furniture
As said before, listing the the evening or on lunch hour - so more people are watching when it ends
Don't take the piss on either the starting price or the postage - it's very noticeable
Pack the tem with the protective wrapping, but don't tape it up, this will give you the weight of the package, the go to Roayl Mail.co.uk, and use the price finder for postage - add about 20-40p for paypal fees and the cost of packaging and you've got your postage price