So you'd like to write some diary entries, eh?
Diary entries are written from the perspective of the character--remember to use "I" instead of Cinderella's name.
Start with Cinderella number one.
When you're writing her entry, be sure to mention the following things:
1) How you are feeling after everthing that happened in your story went down.
2) How you met Cinderella number 2.
3) How you felt about Cinderella 2. Did you like her, or not? Why or why not?
4) What things you have in common with her.
5) What differences you have with her.
6) What you think you'll say to her if you see her again.
Once you're finished--repeat the whole thing from Cinderella number 2's point of view!