Once your AMCAS/AACOMAS is submitted, take a deep breath, relax for a few days, and then start thinking about your secondary essays.
You can look online to see last year's prompts and maximum character counts. While there's no guarantee the prompts will be the same from year to year, the majority of the time they are for an individual school. Here's a brief blog entry on a common secondary prompt: "Why Our School?"
Also, once the AMCAS/AACOMAS is in, take a moment to do some soul searching about what you're seeking geographically, philosophically, and educationally. You want to make considered decisions when the time comes.
Finally, you can start practicing for your interviews. Here's information on my mock interview services.
