Keep your GPA up! Memphis seems to weigh GPA a lot more than they do the DAT. Also do some more shadowing so you get a good exposure to the dental field. I only shadowed for 50 hrs. but I was also volunteering and working full-time (graduated in 2007)...so as long as you're in school full-time and volunteer or shadow some more you'll be fine. Doing that shows them that you're capable of balancing a full academic load with other responsibilities.
Pre-dent extracurriculars...I didn't have any. So I'm assuming they don't put much weight on that either. However, they do take into account your letters of recommendation. That seems to be an important factor in their decisions as well, so keep in touch with the professors whose class you did well in and who you think know you well enough to write you good letters.
Research is a good idea if you're interested in it, but don't do it just because you think it might boost your application. UT isn't a "research" school...they're more clinical and want their d-school grads to be practicing. Although UT College of Dentisty is getting a new dean this year who's supposed to be bringing more research opportunities, so who knows.
If you have a professor in mind thats got a research project that really interests you...I say go for it. That way you're doing something fun and in the end you'll be working really close with the professor and he'll most likely write you a good letter of rec.
Forgot to add about the letters of recommendation....UT prefers a pre-professional committee letter, but if your school doesn't have that then you can get 3 letters from science professors I think.
