good lens, SHOOT IT AT THE LONG END
shoot aperture or mannual, not AUTO
meter the face - use spot or area metering but be careful of bright, or real dark backgrounds and they will cause issues with your exposure
shoot fill flash - but dont use it as a main light in shadows, and turn it down a bit, like -.3 or -.7 or even -1.0 EV is it's too hot. . .
shoot at iso 400 or higher -
use a reflector - get an assistant
shade if you have it - CHECK WHITE BALANCE IF YOURE SHOOTING DIGITAL - the flash will be a different color than the shade, shoot with a diffuser over the flash. . .
Wait for an overcast day for best results, but use fill flash to open shadows and get a catchlight. . .