IMPORTANT things to do outside of just SCHOOL...

VOLUNTEER:  There is a complete section about volunteering on the AADSAS.  I wouldn't say let this section be the focus of your entire preparation for dental school, but they do need to see that the applicant is not completely self absorbed.  I would aim to have have 3-4 good events in there.  Also, try to have a volunteer project that lasts over a span of time, showing that it is a habbit.  I brought food to and visited with a handicap elderly man in my community for about a year. However, no amount of volunteering can compensate for a poor GPA or DAT.

EXTRACURRICULAR:  The admission committee likes to see that their applicants are well rounded.  This your your chance to show that there is more to you than just school.  Do you have a passion? a hobby?  Are you a part of an organization... well tell them about it.  Try to have something you are passionate about or something interesting for your extra curricular or volunteer. If it is something interesting, the interviewers will likely ask you about it and you will be able to talk about something you are more comfortable with.

JOB SHADOWING:  Try to get at least 50 hours job shadowing.  Some schools (West Virginia, Ohio State, etc... like to have excess hours and you will probably need more than just 50 hours.)  It is also important to spread out your job shadowing to different dentists, showing the admissions committees that you have a good understanding of the different ways dentistry can be done and offices can be ran.  Also, make sure your shadowing takes place primarily at a general dentist's office.  I know that on the Ohio State application, they have you fill out everywhere you shadowed and they even separate it out between general and specialty dentistry.  Those schools (like OSU require a certain amount at just general dentists.)  In doing your job shadowing, visit the dentist you like the most just a little bit more because you will want him to write you a letter in the future.