First, do everything in your power to sound optimistic and happy about kindergarten. The less anxious you are, the less she will be.
Take a walk around the school now to get her familiar with it. You may not be able to get on campus, but at least look through gates, peer into windows, etc. Take her picture next to the school's sign. Make it exciting, like wow, look how cool this place will be.
Also be sure to go to the back to school night. There should be an intro night where kids get to meet their teachers and see the classroom.
When you pack her snack (or lunch if it's full day), put a short little note inside (depending on her reading level) that is encouraging/happy. I agree with the teacher who says not to overpack food. Kids get extremely short recesses and lunch breaks now, so they will want to use most of the time for play. Pack small amounts of foods that will be easy to eat quickly (thinner sandwiches rather than bulky ones, GoGurts rather than cups of yogurt, etc.).
Also, be ready for the onslaught of homework. Don't mention this to your daughter, but you will be dealing with a lot in kindergarten. Rethink your weekdays and weekends to determine good times for fitting in homework demands. This can be extremely critical if she's involved in any sports or classes that will limit homework time.
Think positive. Kindergarten is the start of some wonderful times for her and you may also make some new friends (parents of her friends) in the process.