I like to dream big. I set the largest venues, galleries, challenges, etc. as my goals. I then break those challenges down into smaller, digestible components. I assign very specific numbers and facts to these smaller goals. Instead of making an unquantifiable statement like: "I want to be the best illustrator in the world...", I would analyze that, and try to determine the things that would need to happen to make that a ambition a reality. Recognition, accolades, consistent work, quality of work, etc. are all things to consider, and are all checkpoints to help you keep track of progress in your career. I then break those smaller steps down even more. Giving things very specific criteria keeps things from being too open ended, and too grand. "How" is always the best question to ask once you have figured out "What" you hope to accomplish.
Remember, there are things which you are in complete control of: How hard you work, how quickly you grow (this is closely related to how hard you work), recognizing opportunities, and taking advantage of them, what you know, and what you learn, being a great student with a curious mind (this should last your entire life), your willingness to share, to be taught,surrounding yourself with more talented people, more driven people, etc., committing to you goals and embracing them as part of your lifestyle, etc.
Equally as important as what you do , and those things that will help you to attain your goals, are being aware of your weaknesses, and the things that will keep you from realizing your dreams. Beware of laziness, nay sayers, arrogance, unchallenged fear, and life choices that take you away from your path. Often times, bad habits from our life in school continue to affect us long after, especially if we live in the city where we graduated. There are associations with people that are unhealthy, and decisions made out of boredom that grow into bad habits and addictions. Do not let the doubts of parents, friends, family, boyfriends/girlfriends, wives, or anyone for that matter direct your life.
I moved to Kansas City soon after graduation to be around a group of artists affiliated with the Illustration Academy. It broke my heart to leave my new girlfriend behind (she is now my wife), and being away from this life that I had established in my home town was the hardest thing that I ever did. Still, all of my distractions fell away, and once I got over my "social withdrawal", I was able to focus on my goals. The year in Kansas City became one of the most important times in my life.
I have noticed that that the rare moments of true, soul-fulfilling contentment in my life are always on the heals of fears that I have faced. We tend to fear the unknown. If knowledge is power, then the more we learn, the less we fear.