Speak with her teacher about finding a couple of "buddies" from the class as guides to find her away around the school, take her to the lunchroom, etc. and generally help her out for the first couple of weeks until she settles in.
Find out if there are any other new students with whom she might bond over their shared experience.
If there are there some co-corriculars starting, she'll probably make new friends fairly quickly by joining - library club, games club, choir etc.
If you can manage it, hang around a little before and after school and scope out her classmates a little. You may recognize a kindred spirit (like the kid carrying a dog-eared copy of your dd's favourite book). Chat up the moms a little too. If she sees how you are making new friends, it might help her to do the same. After, you can talk with her about and share how you feel and role play with her, so she can try out some different approaches to the other students.
Best wishes to her - and to you. I know it isn't easy watching your little one trying to fit in and make new friends.