Keep asking questions, keep posting discussions, keep commenting on stuff. Link out to other people. use your blog if you have one, or Twitter or somethignng. Traffic is traffic and so's exposure. It's harder for me to target the druids and the paladins because I'm not as well versed with them as I want to be.
Pretty much this.
I posted as much stuff as I had time to do leading up to Cataclysm, and we had some good discussions going then. At least as far as I've seen druids stand in a much better place going into Mists of Pandaria than they did in Cataclysm (If I'm wrong please correct me), there was quite a lot of QQ about not getting a new spell for Cataclysm, the changes to Tree Form, and that lead to more discussion.
I have started playing a bit again, and if I find time I may try to update the content Matticus has published in the MoP forum... but right now it's kind of daunting because I haven't been keeping up with the beta news this entire time so it's a lot to digest.
In the meantime though, I thought Jasyla had a nice blog post about some of the changes so far.