We do the same.
We generally start with asking the student to us us about themselves, their outside interests- this hopefully gets them to relax.
we also ask about outside the classroom activities - like research, volunteering, special dental projects, help missions.
Biggest suggest - be your self
PASS of interviews:
P- Presentation - look good, present with a wide awake rested appearance
A- Attitude show you are interested, read the material about the
program, ask questions, show that you are willing to work
S- Scholarship show you are qualified, explain your record (if any problems)
S- Skills any special skills you have used like trips to tx patients,
volunteer clinics, Special programs you attended/gave,
foreign languages you speak.
that is some ideas