My biggest takeaway after 5 years:

- Make contacts. Talk to everyone, be on friendly terms. I say "contacts", not "friends". You may not like these people, but they are going to be working in the same field as you. Get out of the clique mentality prevalent in high school - you're all there to graduate with a useful skill-set. That asshole sitting next to you might be your boss tomorrow, or your colleague, or the guy who interviews you for your dream job. Don't burn bridges before you've had a chance to cross them.  

- [b]Learn to be your own hero.[/b] I can't stress this enough. Don't rely on your parents or friends or professors or anyone else for that matter. In the modern world a person has to be completely self-reliant, sorry but that's just the reality of it. Especially when it comes to the universally despised group projects, you should always anticipate and prepare for someone flaking on you. The professor isn't going to care that Jake got too stoned last night and couldn't submit his part of the project. Always have a plan B. 

- Learn to use Google. Love it, cherish it, because this bad boy is going to be the biggest factor in getting that degree. This isn't school and nobody is gonna spoon-feed you information, you'll have research and find it on your own. By this I don't mean going to Google and searching for "how to solve xyz". Learn how to search within specific fields. Look up scientific journals that pertain to your interests. This all comes in handy when writing a course work or something along those lines. Check this, a quick way of improving your Google-Fu: http://lifehacker.com/google-tips-and-tricks-every-student-should-know-1508121671 

- If possible don't start a job until your 3rd year. I made this mistake and it's cost me two years of my life basically. 

- Don't break up before your exams. Just don't. 

- Gain extra certifications while working on your degree. This is very specific depending on what you're actually studying. In my case, I study informatics and comp sciences, so degrees from Cisco, Microsoft, VMware, etc are incredibly important. Depending on your field, they are often more precious than your diploma. 

- Learn a new language. Every language is a door to new job opportunities, both at home and abroad. Best time to learn languages is while young, so just go for it. 

- Finally, don't forget to live it up. Life might seem incredibly complicated and busy in college, so people often think "OK, I'll push through these 4-6 years, then enjoy myself". Don't be that guy/gal. It's only going to get harder from here and you'll have less and less free time.