Sharing these two helpful links from Katrin's session today.

The exam outline is really important and is the best way to find out topics that weren't covered in the trailhead modules. User interface under org setup was one of them. 

https://trailhead.salesforce.com/help?article=Salesforce-Certified-Administrator-Exam-Guide#outline

Examples of validation rules: Seems very handy for the future as a reference.

https://help.salesforce.com/articleView?id=sf.fields_useful_field_validation_formulas.htm&type=5

Also, are any of you giving the exams in the next month or so? How many hours every day do you think you'll be putting in till you give your exam?