For such a long commute invest in some puncture resistant tires, and lights that will last the 1(+) hour of commute. I recently started a new job that takes me on some country roads which are more scary than the city streets I used to ride. Like mentioned: Be Visible! I am not sure if people aren't used to cyclist, but they don't obey the 3 foot passing law as required on those narrow country roads.

I would also make sure you know alternative routes. Another thing I found out the hardway was also know the public bus system (if you have one). I got into work without issue, and when I was ready to leave my rear tire was flat and I had no spare or pump. So perhaps also learn how to change tires and maybe keep some tools in your locker at school.