As stated above, College already tries to avoid this pitfall by putting students in labs and facilities and out in the field whenever possible. Perhaps a more apt description of what you should be aiming for it "don't limit your education to the syllabus." Join some clubs, participate in the social experience, and don't let the assignments and tests turn you into a hermit. Social skills and life experiences are just as important to your intellectual development, and important to developing a network as well.
In the working world, who you know will be just as important as what you know. That's the purpose of a professional network. It's a group of friends and colleagues in your career field you know and communicate with, who can provide you with opportunities and tips. Getting one started in college is simple: Get to know your classmates and professors well enough that you can communicate with them post-graduation, and you'll have a running start.
You will one day need to prove your skills to a prospective employer, and simply having your degree to show may not be enough. Instead, you need tangible evidence of the things you've created, and fresh out of school, that will be your assignments and projects. So whatever you accomplish that you're proud of, document it. Keep the papers, keep the photos and video, keep some evidence. If you can build a personal website, even a Wordpress to stash it all on, then do so. In the long run, you'll want to eventually cease using schoolwork in your portfolio, but for now, it's a good foundation.
A lot of college programs have some sort of internship, field placement, or co-op built in, and they're well worth doing. On the off chance your program of choice doesn't have one, it's worth seeking it out independently. While you might balk at the idea of free or underpaid work (though that is rapidly changing thanks to new legislation,) it does provide you with valuable real-world work experience of a type the best college class can never simulate, as well as a link to more portfolio and networking opportunities. Obviously, you'll also have to make sure you're doing more than getting coffee for your boss, and after that first internship, you should only accept paid work, but doing at least one can enhance all of the above actions.