Any advice for a n00b to fanfic? I'd like to start writing but I'd like some advice.

Don't take any criticism too much to heart. A lot of fanfiction writers with great ideas and potential stop writing because someone trashes what they write or is really rude with criticism. With that said, good luck to you!! :~) I'm sure your writing will turn out beautifully.
~Anneryn

1. Come up with a skeleton for your plot - an idea for where to start, what you want to happen in the story, how you want it to end. Otherwise you might find yourself blocked midway through writing, and it'll also be a bit obvious in the lack of structure for the story.

2. Write out any scenes or lines which immediately come to mind, even if they'd be set later on in the story. Don't tie yourself to writing it in chronological order.

3. Re-watch/re-read the original to remind yourself of what the character should be like, and any background/lore/mythology which you might need to reference in the story.