This help?
1. NEVER ACCEPT ECHEQUES FROM AN UNCONFIRMED ADDRESS - if you do, and they reverse the transaction, you are NOT protected by PayPal
2. CONTACT YOUR BUYER BEFORE SHIPMENT - send a recorded letter to the address (a receipt maybe). This will require their signature and will prove they live their.
3. INSTRUCT YOUR COURIER TO DELIVER INSIDE - under no circumstances should they hand the parcel to anyone who 'appears' from an alleyway or come in through the gate at the same time.
4. CHECK YOUR BUYERS FEEDBACK - first stop for many, see what others have said
5. EMAIL THE BUYER - try and obtain a telephone number (landline would be best)
6. FOR HIGH VALUE ITEMS - check the electoral register for their address, updated regular and is a good source of information
7. DO THE BUYERS NAME AND ADDRESS MATCH THE ACCOUNT DETAILS? - Check that the PayPal account belongs to the buyer, if it doesn't, refuse and report immediately.
If you are in any doubt at all, then refuse the payment and request an alternative method. Genuine buyers will be happy to do this, scammers will be determined to pay by this method.