I've been helping some friends with their resumes lately, and it's caused me to think a lot about how I became a sysadmin. I don't have any formal training (beyond some vendor-specific stuff), and I didn't go to college to be an IT guy. I have a computer science & engineering background, which has lent itself to a lot of what I do and know, but the engineering and CS skill set is not the same as an IT guy. In fact, most CS departments seem to not want to teach sysadmin-type skills, "because they aren't a tech school."
So how the heck do you learn these skills? And, more importantly, what are the skills you need to learn?
I've been a help desk support person, which taught me linear troubleshooting, and my science background taught me to change only one variable at a time. That's very important in my life in IT, and a skill that I try to teach more junior admins.
I've been a software developer in the past, and can use programming languages and scripting languages to help make my life easier. Being able to do even basic things like loops, in UNIX shells or PowerCLI or Perl, lends itself to a lot of time saved.
I've managed a number of projects, and through that have learned good time estimation and prioritization, but it's taken a lot of time (no pun intended) to improve my skills.
Troubleshooting, scripting, and time management are not all you need to be a sysadmin, though. What else am I missing in my list, and where do you learn it? Or are there innate qualities to a sysadmin that are unlearnable through any practical means, but that we look for when we hire people?