One thing you might want to try is pulling her farther away from the flowers, and I don't know what camera you have, but with a smaller DOF they will fall out of focus.
Most people hate shooting in full daylight, but the best method around that is to bring a white board. Yup, a white foam board you can pick up at a Staples or Michaels for all of $3. Have them hold it a little ways out from their waist pointed until you get some nice sunlight on their face - meter to properly expose their face, and you have gorgeous backlighting.I'll check that out, thanks for the advice. =)
One other thing to watch out for is to amke sure that either her both eyes are entirely visible or only one. In most (yet not all) cases it is more appealing. That's a rule right?