One thing to be aware of up front....there are far more people in your shoes than owners who need to rent out their property from time to time. ESPECIALLY if you are looking for the high demand, low supply properties (i.e. you can find an SSR owner or a VAKL owner to make a reservation - finding a BWV or Poly owner is a different story - they are there, but their points get snapped up quick).
DVC reservations are best made as close to eleven months out as possible.
There are basically two bridges to cross with availability from a rental standpoint - you need to find an owner who has the points you need to book - and if you are looking for a high demand resort, you'll be at a disadvantage. And you need to find that owner in a timeframe where room availability for the room you want is still open - the closer you are to eleven months when you find that owner, the better the chances are that the room you want is still available. The closer you get to seven months - or your trip - your chances shrink until you get to "have you bought a lottery ticket recently."
Don't expect to be able to rent rooms that are a great value. i.e. there are very few VAKL value rooms, they disappear fast. Getting a rental for a BWV standard view room is tough, especially during the last three months of the year. If you are trying to get one of those low point rooms, be clear to the person you are working with if that is all you will accept (in which case, you may get locked out) or if you'll take the more point option if that is all that is available).
An owner at VGF is not going to have access to special rooms another owner at VGF doesn't - if one owner has told you it isn't available, that means it isn't available, not that you should keep shopping (and wasting an owners time) looking for a different answer.
I say this because I think the biggest issue I see from first time renters is frustration that this isn't calling up CRO and booking a room. This is more like getting tickets through a legal scalper to a concert. If you are looking for Taylor Swift, good luck. If you are looking for Nickleback....