I used ti be obsessed with her books when I was in Primary school and early Secondary school. The one that always stood out for me was "My Sister Jodie", where she falls from the window. There was also the "Girls" series that I loved. I'm pretty certain I remember one about 5 friends who had sleepovers on each others birthdays too. Diamond Girls, Kiss and the one about the girl with the famous Dad was good as well.
There's also one that I remember about two girls who were best friends and one was really rebellious, and their parents tried to keep them apart.
After reading Jacqueline Wilson books, I also read the Mates, Dates books by Cathy Hopkins, and I was also obsessesed with The Chocolate Box Girls series by Cathy Cassidy, and even got the book Coco Caramel signed by her, and my sister got the Daisy Star one signed