Well the main one was just learning, know more people and I thought I would learn how to start or make my own company.
Look, the best part was knowing a LOT more people, learning from them, and just getting all that business stuff/crap/insights...
But the single best and most important advice I could give some one that doesn't want to take a full MBA, it's:
1. Learn finances, OMG, just do it. Loan payments, ballon payments, how interest works, credit lines, bonds, leisures, etc. Just LEARN IT, its really usefull, no matter how, just learn it and really well!
It's one of the single most important things you could learn as an adult.
2. Learn Marketing. Not just the social media crap, but the "Emotional Branding" stuff. OMG, GO GO GO. Learn to creat "experiences" with the senses, to manipulate prices, learn the marketing lingo and feel the bliss of learning how to sell your producs.
DO. IT. NOW.
Anyway, I'm getting my degree in about two weeks. It was hard. It was fun, and actually cheap (third world country yey!).