I'm basically a complete beginner (I've watched a bunch of anime but that's about it) and I've just started RTK (done about 100 Kanji) but I've been wondering what your supposed to do after you've finished or while your learning the Kanji to help you understand the language better. Should I start learning the Kana? Or should I save that for after I've done the Kanji?

I've been trying to follow the AJATT (All Japanese All The Time) method. So I'm listening to a lot of Japanese everyday. But should I be doing something else?

You should learn the Kana ASAP! They're really easy; I thought everyone learned them before doing RTK. If I were you I would just pause and spend a day just drilling kana, since they're the kind of thing you can understand just by drilling, there only being about 100 completely different "primitives" if you like. Beyond that, just the act of reading random Japanese every now and then will maintain your ability.

Most people here thing you shouldn't do anything else during RTK1, but around 1500 many start a sentence deck in anki, and after it so do the rest (this is a great way to gain vocab and grammatical proficiency) So until you've gone further, I wouldn't worry about anything. All up to you, though.

I wouldn't want to say there's such a rush with doing the kana so quickly, but it's easy to do while you're doing RTK and it doesn't take so much effort, does it? You can make an Anki deck and perhaps use pictographs like in Remembering the Kana.

RTK gives you a great foundation for learning words, so getting it out of the way fast in order to move on to vocabulary is a good idea. You can mine sentences or use pre-made decks like the Core decks. http://forum.koohii.com/showthread.php?tid=5110

Keep up the exposure to the language and get into reading and vocabulary once you're done with the characters.