If you want to pass RHCE then setup two Linux systems at home/work and start practice everything.

It is not that hard but all you need is tons of practice. And if you have any problem then just start to post your question here in Linux forum

All the best for your studies

Common problems that I face so far at my work place:

Server crash
RAID crash
New hardware is not detected by RED HAT
Boot loader problem
RPM problem such as dependencies
Server hacked
And few more which I am not able to recall right now