Q: What do you wish you knew about your job when you first started out?
Linux Systems Administrator in Seattle:
"Demanding Work, Rough Hours - But I Make The Internet Happen!"
Introduce yourself to the world of free and open-source software and start playing with Linux. I didn't get serious about it until a few years into my career and once I got comfortable doing things "the UNIX way" I could never look back.
Once you're free to use the full power of your computer, go ahead and "tinker" with different software packages. Set yourself up with a little server farm (I got a few cloud VPS servers for about $10/mo. Total) and set up a domain name and website, with email, your own DNS, nagios monitoring and automated alerts, log watch, puppet/chef config management ... At some point, you will need to know something about all of that stuff and setting up a simple implementation is a great way to quickly learn the basics. Plus, I'm a big nerd and think it's super-fun.
Finally, learn a modern scripting language, such as PERL and/or Python. Along with good BASH skills, these enable you to build complex automation/management tools that will make people love you.