I thought it was pretty cut-and-dry for the most part. For your essay, you may want to use a simple text editor instead of Word, before cutting/pasting it into PTCAS just in case special characters don't translate well. Also, be sure to check with the individual colleges regarding whether they want forms filled out for the PT places you shadowed or worked at.
Aside from that, just start picking away at it as early as you're able to...it took a bit of time to get all of the stuff filled in and the transcripts sent to them and all that. A few days after you submit it, check w/the college rehab departments to make sure that they got your application.
It's pretty convenient being able to submit to so many colleges from one application, although my impression was that the trade-off is that there are a lot more applicants to each college (at one of the universities I applied to, it had about 25% more applicants than last year), and subsequently a lot more waitlisting.
