Basically, what you need to do is this:
Keep getting involved in regional RPs that are open to you. Like the Stories From Astyria thread is always open to willing participants. You do need to apply first: http://forum.nationstates.net/viewtopic.php?f=4&t=297977
Several members often have diplomatic or crisis threads. Or...you could plan a diplomatic thread of your own out with someone in Astyria or Probation.
There is the annual Alpen View Brew Festival thread that happens in the fall. That's always open to everyone, within certain rules. Read up on that and apply here: http://forum.nationstates.net/viewtopic.php?f=4&t=211832
Keep doing your thing in the diplomacy threads, whether that's sports, diplomacy/character RP, II/war, GE&T or even Portal to the Multiverse. Just get involved. We don't count the General forums as RP, except for P2TM, so we'd recommend staying away from General and F7 unless you have unlimited time and can get both solid RPing and yukyuking/debating in.
Keep checking out both RMBs in the main and probation regions. You may not be able to post in main, but you might catch something we forgot to post over in probation.
IRC. Jump on there when you can to our regional channel, link in the probation WFE. Talk to us, ask questions.
All these things are optional, but they will get you 'points', so to speak, towards entry to the main region and have us members knowing that you want to be an involved, active, equal part of Astyria.
Additionally, if you don't hear about your status after a month in probation, a gentle TG reminder to the WAD is acceptable. If you haven't gotten into the main within a month, don't lose hope. They may be taking time on voting you in, or are looking for a bit more visibility from you.