Things done by a Systems Administrator on daily basis?

Hello everyone

I am learning Linux so as to become a professional System Administrator in a big IT company and as i prepare for that, i would like to know the common aspects of System Administration that i need to learn.

If possible i need a list of the topics or areas where i should gain more System Administration knowledge in order to prepare for my dream job.

And i would also like to know about the the daily activities that most System Administrators do.
I also suggest that feed backs should come from experienced users.
Thanks.