One.
Make an entry (FO, for all people... whatever you want) in your lj. The post must have a list with 10 Christmas wishes. The wishes can be anything you want, from something simple related with the fandom (as a fanfiction), something intermediate (" I would like the DVD of blablah "), to something really difficult ("For Christmas I want a new a new car/cd collection/blablah")... The most important thing is that you are sure, that those are things that you really want.
If what you want are "real" things (not fanfictions nor icons), make sure that you include some form of contact in your post, your address or an e-mail where people can contact you.

Two.
See your F-list(or the F-list of your F-list) to check if someone had posted this entry. And the most important: If you see a wish that you know you can give and you have all the intention, make that the wish of that person come true.