Detailed Review Of Preparation

There are a few things to consider. One is to read and practice. The more you read and practice the more you will remember and understand. I said 60 days to prepare for the exam. Which was a rough estimate. This varies from individual to individual. I was studying almost every day for 2 hours after work. Bear in mind I am Salesforce Admin for nearly 3 years already. But if you are completely fresh you will need 2-3 months and more than 2 hours a day to study that's for sure.

Learning Material:

Traileheads are a great way of getting the bigger picture of the Salesforce features.

Mike Wheelers videos show a nice presentation of each relevant topic and feature to visualize.

Focus on force gives you the ability to take mock tests and if answers are incorrect you will get the explanation of what was wrong including the screenshots and link to Salesforce help files. 

The most powerful material is in fact Salesforce help files. There you will find all the details possible to help you with your exam. 

Good Luck!