What are some good ways to help a middle-schooler handle stress at school?

My daughter will be starting 6th grade soon, her second year of middle school. The school is large, with lockers and transitions from class to class. Last year, she often said she found school very stressful because of the changes from room to room. We thought she would adjust as the year went on, but even at the end of the year said she still felt more and more stressed as each day progressed.

She also started getting migraines from time to time. We can’t find any common triggers in her diet or sleep pattern, but she didn’t have a single migraine over the summer. It could be the stress of school. She’s a good student, gets good grades with very little effort, and has her best friend in almost every class.

What are some strategies we could use or help her learn in order to manage stress? I was thinking of talking to the school counselor to ask for advice. We are also going to have my sister-in-law, a middle school teacher herself, help our daughter decide on an organizational scheme that will take any worry out of getting to class prepared. What else can we do? Thanks in advance!