I'm a non-traditional student that will be starting DPT this fall and here is what I did...
I focused on getting A's in all of my remaining pre-reqs (while forming good relationships with my professors so that I would get a great LOR from one of them) and studying for the GRE with a goal of 1100. Also, while taking my prereqs I got involved with my community and starting volunteering with a variety of programs. I tried to choose programs that would either demonstrate leadership (ie coach, camp counselor, official, etc.) or ability to work with a diverse group of people (ie young, old, disabled, etc). Along with volunteering I started a youth injury prevention program for the youth sports leagues in my community.
I shadowed at as many different clinics as I could when I had some free time. When school was done I decided to get a job as a PT aide (even though it was a HUGE financial blow) which allowed me to be around PT 40 hours a week and learn a great deal about the profession. I worked in a big clinic with a lot of therapist with different specialties and that exposure allowed me to become educated in current events and different aspects of PT, which gave me a great deal to talk about at the interviews. It also allowed me to form great relationships with PTs, which in turn produced great LOR's. Working with many different therapist really came in handy when it was time to write my personal essay, as each of them were willing to critic it.
This response is getting a little lengthy so in conclusion I will say... get your numbers as high as possible, be able to demonstrate leadership and ability to work with a diverse population in your extra-curricular activities, write a great personal essay, and get great LOR's (both from PTs and professors) and you should be in business.
Good Luck!