If you want to practice your CCNA skills, you should use some kind of exam simulation in order to see that how competent you are and in which topics you still need to work. Here is a link where you can find different kinds of free exams related to CCNA. For example, if you are going for an upgrade exam, you should click on the CCNA upgrade exam and if you want to go for the new 640-802 exam, you should click that. Access the practice exams from here:

http://www.howtonetwork.net/public/department33.cfm

The video below shows you how to access the free exams.