1) Try not to sell on eBay. Perhaps Craigslist or another marketplace will work instead. Unfortunately, people in low population density areas are kind of screwed without an online marketplace.
2) Block all buyers from countries other than your own. In massive markets like the US, gaining a few more potential buyers is not worth the increased risk of fraud or loss during shipment. Perhaps in smaller countries this rule won't work as well.
3) Only sell to people with significant positive feedback.
4) Only ship to CONFIRMED Paypal addresses.
5) Require Signature Confirmation for items over $250.
6) Don't accept PayPal; require money orders for payment. This might scare off potential buyers. However, it has the benefit of taking PayPal and credit card chargeback schemes completely off the table.
7) Don't ship General Delivery.