First things first. Your timeshare probably has zero resale value. The Central FL area is flooded with timeshares that can't even be given away. Make sure you are well aware of the realistic resale value of your unit. If you are serious about unloading this, you can start advertising now.
Use reputable websites such as RedWeek, E-Bay, My Resort Network, or Timeshare Users Group (aka "TUG"; tugbbs.com). TUG has a Bargain Deals section where you can list for free that you want to give your unit away.
The most important thing that bears repeating is to never pay anyone a large, upfront fee to sell, rent out, market, or "cancel" your timeshare. Any outfit that asks you to do so is probably a scam.
Lance C.