What is the best way to sell a timeshare for fair market value?

Can you answer runs_with_scissors’s question about Timeshares?:

There are a lot of scam artists who ask for an up-front fee to cover their “marketing costs”. There is no guarantee that they will ever sell your timeshare. And, if they’re being paid up-front, they have no incentive. Any ideas?

Buy a Las Vegas Timeshare