For the Developer certificate we advise you to follow the Designer and Developer training and have 6-12 weeks of hands-on experience.
For the Administrator certificate we advise you to follow the Server/Publisher training and have decent hands-on experience with servers.
Reading the books you get with the training gives you enough information to at least pass the Developer certificate.
You can find a skill assessment here:
See those as practice questions similar to the exam.
For more information about certification, see here:
All of the information about the Qlik Certification Exams can be found on our web site with the link provided by Onno.
I HIGHLY recommend reviewing the page for the exam you are taking - there is a list of Prerequisites and Recommended Preparation Resourses - then STUDY the topics in the Exam Domain Areas section. These are the testing objectives from which the questions were written. Hands-on experience with the product is a must!
Certification Program Manager