My parents are actually pretty cool about my intense nerdliness, and I've even tricked my dad into bobbing his head along with a J-Rock song
As for advice, maybe focus on the kitchier of anime, instead of venturing into the deep dark abyss of echhi and hentai
As for cosplay, I'm also a n00b, so power to you! The cosplay thread is full of plenty of useful info, and helpfu people
I second the motion, though, of going as a random shingami d00d