Originally Posted by
Tartegnin
Wow again - all great advice, especially about pinpointing the anime. She will want to see the Pokémon store for nostalgia (she's "moved on"). Absolute top favorite in Anime is Hetalia.
Perhaps of interest to you then: a Nekotalia-themed cafe in Anime Plaza's Akihabara store, open until 28th June. Here are the links to the (Japanese) Hetalia and Anime Plaza sites:
http://hetalia.com/twt/event/1188.html
http://www.adores.jp/anipla/nekotalia-ak/index.html
Not as sure about manga, as she reads whatever she finds at the library. I understand the manga will be mostly in Japanese anyway, so she's better off buying that here.
Complete manga sets can be had dirt-cheap at Book Off. A perfect excuse to start learning Japanese.
She has done some cosplay at a couple of "cons", so that may be of interest, too.
There's Cosplay Festa on 4th/5th June in Tokyo Dome City and Cos-Day on 12th/26th June in Tokyo Big Sight. I'm not really interested in Cosplay, so I have no idea how open these events are. Since Tokyo Dome City is open to the whole public, it could well be that you can see cosplayers there "in the wild", but for the events itself you have to register as either cosplayer or photographer in order to attend, I think.
I also know some of the genre can be quite sexual and/or violent, so would want to steer away from that.
Then be advised, should you venture through Akihabara's stores, that there's mostly no kind of physical separation when it comes to R18 stuff. So it's entirely possible that you stumble about it in stores.