Well, nobody has this down to an exact science, but here are some things you can do that might help your chances of getting noticed by the Pin-dispensing Fairy Godmother...
1) register an email address on the Disney parks website
2) fill in all the profile data, and include such tidbits as when you were there last, when you think you're going to visit next, and so on
3) shop for some package deals, picking dates, resort, ticket package and all, then save that into your "hold" page
4) go to the "My Disney Vacation" page and save some alternates
5) order the current WDW planning DVD
6) participate in the games, click on the links, go to the websites referenced in emails from Disney Destinations.
There are some more, but that'll get you started. When you've done all that (for at least one email address -- some people register many more), come back and let us know if you get a pin.