if you wanna be like the other SDN'ers, have your AMCAS primary ready in June (pref opening day if you can, but def by mid-June cuz it takes a while to verify).
This means you'll want to have your MCAT scores before then, so like April/May latest.
Secondaries will start piling up your mailbox in July, again, if you wanna be like SDN people you'll start sending out secondaries in July, but I think August is fine too.
Another big thing, do not wait on asking for letters of rec. Some profs can be very lazy about this, esp if they don't know you and have 20 other students asking for letters. The last thing you want is to have all your apps ready, but EVERYTHING is on hold because of ONE letter. Schools will not even look at your secondary until everything is in. So get those LOR set up early.
edit: one more thing, make sure you understand how your school handles LOR requests. I sat down with my advisor for a good hour to fully understand the process and make sure there were no delays. They are your best friends... them plus SDN people.