I've found that creating a good network of trusted and talented peers and professor during college, and nurturing those relationships afterwards allows you to explore more possibilities than going it alone. Some designers in college can be territorial, competitive and in some cases cut-throat. But when you free yourself of the ego-centric competition with others, and challenge yourself to be the best for you, while embracing others, you create a more powerful creative engine that transcends myopic competitiveness, and generates deeper creative ideas and opportunities. During my college years, I surrounded myself with many of the top designers in the school. This also has the effect of elevating your own skills through ad hoc critiques of your work with the trusted group. Many of my post graduation jobs and contracts actually came from my professors and peers.
Also, take advantage of as much pro bono work as your free time allows (but, try to creatively workout other forms of compensation, E.g., I'll design your logo pro bono, if you contract me to design 'X'), since; 1) It's a great learning opportunity, and 2) These types of jobs lead to future work and recommendations after graduation. But, all of the above is irrelevant if you don't put in the work! Work harder and smarter (key being smarter) than your peers. Become a sponge for information. Explore the latest design models and technologies. In a nutshell, never stop asking yourself what can you do better – and do it!
In terms of happiness and income – find what you're truly passionate about and love in the world of design. That makes all the hard work you have to put in feel effortless (or less hard:-). When you love what you do, epiphanies come more often, and the work doesn't feel arduous, but almost effortless. Be passionate about what you do and an advocate for yourself and your skills, and nurture professional and private relationships. This type of strategy has a compounding effect that will reap benefits long into your career.