I'm a freshman going to be a sophomore in college, majoring in Computer Science. What are some things I could be doing (besides chilling - done too much of that) in order to further my career?
I have a job, but I also want to do something with all the time I have, in this glorious time of no school called summer.
Write code. Lots and lots of code. Making a working application and refine it. Tweak and improve it until there's nothing left to do and then release it as open source and invite code reviews.
The more code that you write now, the better-prepared you will be to enter the workforce as a competent and confident contributor. You'll remember all of the theory that you learned in classes because you put it into action.
All I can say is enjoy your time. Decompress and if you still have time after that, perhaps you would like to try some sample projects using JQuery, Microsoft Frameworks (Entity Framework, MVC 2, Enterprise Framework, etc). If you like Java consider learning Groovy or something like that. Other than that enjoy your summer.
Get involved in a FOSS project of some sort, something you're interested in rather than necessarily a high-profile one. I say one you're interested in (be it a basket-weaving pattern generator or a database for 14th century torture devices) so you'll have some impetus to do more.
That way, you can have something to put on your CV and you'll be doing useful work as wel.
Well aside from the job that you already have, you could join and contribute to an open source project, you could teach yourself a technology, programming language, or framework that you currently don't know, or you could create your own open source project. That said, work isn't everything. Live your life. Hang out with your friends, go outside, have fun, maybe work on a community service project or something. While it is good to pick up experience, it's also good to be an all around person.
You did not say if the job you have is related to CS but if it is not then do an internship related to what you want to do in the future.
You know the big room through the doors?
The one with the blue ceiling and the bright light?
Go out there and move around a bit.
If possible try talking to girls (sorry there isn't a manual you have to sort of reverse-engineer the protocol from their responses.)
From a hiring manager's perspective: If you can, get an internship at a company with a real brand in software (as opposed to working IT for your school or for any other non-software company).
If you have an internship from Google, Microsoft, Yahoo, Facebook, Oracle, etc, on your resume, I will almost certainly move you to a phone screen stage based on that.
Worked the help desk at school? Made a web site for your local dentist's office? Those might be good lifestyle gigs but they don't tell me very much as a hiring manager. YMMV.
Is there something you've dreamed of doing but never had the time? Never had the initiative? Never felt confident enough?
It's time to try.
In my case, I basically wanted to build an operating system. So, I spent two years gradually building a kernel in my spare time. Not long after, I got a job as an OS research engineer, a job that I enjoy tremendously.
That was six months ago, and I'm still a university student.
So, get some experience in something you find fascinating. It might help you land a career in something you find fascinating.
When you're ten years older putting in extra nights and weekends without receiving overtime, futilely hoping your boss will recognize this and grant you just a couple extra vacation days to help soothe your aching back and repetitive stress injuries, you may regret not taking advantage of your youth and freedom while you could have if you don't RIGHT NOW.