My advise to you is to take care of the recommendations first because that's something you can't do on your own. That takes, not your time, but others'. Others that are above you, who needs to see you in good light: ie your professor, your boss, your contacts in administration, and ect...
Second step is your essay. This takes time to organize, not paper work organization, but your thoughts on how are you going to effectively and creatively or even logically justify your wish to join this profession.
Third step is easy, your AADSAS application materials, and all you need for that is transcripts form all your post secondary schools that you attended. And you also need your resume or CV to list your experiences and community services (When, where, and who) This step, if you have all the necessary papers, you can do it in one or two days. (few schools are not part of AADSAS, like the almighty Texas schools) I don't know why? (and the Canadian schools) don't know why either! The AADSAS starts accepting applications June first, so I would recommend to send it in as soon as first of June.
So by the time you are ready so submitt your AADSAS application to AADSAS, you should have your recommendation in school file (or send directly to your school of choice), your essay, your DAT scores, and your official transcripts that's ready to go!
Timing is also important, it depends on when you will take your DAT (you get your scores right there and then), so all you have to worry is just studying and doing well on your test day. So ideally, take your test before June and have your scores, and send out everything around June of 2003. (It takes about a month and a half to be processed by the AADSAS, and another month when it arrives at the schools of your choice.) If you do this, then you should get back your interview invitation around Sept or October, and you would set up your interview around October or Nov. Then it takes another two weeks or a month after your interviews to get your results back.
I personally took my DAT late October (I pushed it from Sept), and I sent my application early Nov. ( So I was late by two months and I was litterally crapping in my pants) but luckly I started getting interview invitation by mid Dec. and early Jan. And I held my interviews during Jan, Feb, and March (one everyweek) and I got back from all the school I wanted to hear from, but there are few that needs to come in but I couldn't care less now.
Hey hope my stuff helps. Study Hard, Plan Early, and Good Luck with everything!