The earlier you start to plan, the more options you will have. Owners at each resort can make reservations at that resort 11 months ahead and at other resorts 7 months ahead so if you are looking for a specific resort more than 7 months ahead you'll want to reply to onwers with points at those resorts.
Availability will be best at 11 months, but there is often something available within 7 months for may times of the year as ling as you are flexible with your dates, resort and type of villa. Within 60 days, any DVC villas not reserved by DVC members are turned over to DRC for cash reservations so the last 2 months are often tough to find reservations.
I'd suggest going to the DVC Rent/Trade Board and responding to threads titled "Points for Rent". Most will also have information about which resort(s) they own and when their points are valid. Just look for those who own where you'd like to stay to have the best chance of success.
Another option is to contact David, owner of www.DVCrequest.com and one of our DIS advertisers. He has access to many owners at all resorts willing to make reservations for others.