We rented from another member to add a few days to a March trip we were taking. I looked on the rent points board on this site and made arrangements with another member to rent some of her points. I guess we had a couple of different options. She said she could transfer the points into my account, or I could just have her make the reservation and send me the paperwork. I just had her make the reservation and then I sent her the money. After she received payment, she put the reservation in my name.
You can also borrow points from your next year of points if you have a big family trip in the works. We've got friends that are doing that this summer. They said the down side was they wouldn't have much points left for next year though!