I don’t know what book you’re doing the WT1 on so I cannot provide suggestions on the content, but here are some general pointers to pay attention to:
• Format - diary entry has a date + [optional] time on top, start with ‘Dear Diary’, consider using a handwriting font, and end your entry with ‘See ya tomorrow’/‘will keep you updated’.
• Point of view - diary entries are always written in 1st person.
• content: write as if YOU are actually writing this diary entry. It contains information only you want to keep to yourself and is very personal. Whilst keeping this in mind, your mission in this WT1 is to demonstrate you understand the context and even better, the nitty-gritty details of this book. Find a way to integrate that
Last but NOT least, don’t forget to always refer back to the criteria. The criteria literally shows exactly what examiners look for when grading your work.