The first year in a new environment, it is important to take on the attributes of a sponge. Take in as much as you can. Lead by being a great follower. Execute the plans of the current leaders, and do it in a way that lets them know you are there to genuinely support them.
It is interesting to note the contrast that happens in the first year of a transition. For instance you may go from being top dog, seniors that rule the school, to the "Freshie". When this transition happened for me in college, I let down a lot of barriers, changed my expectations for myself, and just tried as many new things as possible. To put it in perspective, during my senior of high school I wore heels 95% of the time, biked to school, worked 15 hours a week, and spent equal amounts of time blowing my cash shopping. I was passionate all right, I was passionate about expressing myself through my dress. While I was working and contributing to society in that regard, I was not doing it for anyone but myself.
On the flip side when I got to college, I purged my over-consumption, occasionally wore sweatpants to class, stopped dyeing my hair, got super involved on campus, and dedicated myself to my school work and meeting new friends.
These experiences were formative because I didn't let my perception of myself in high school get in the way of who I was to become in college. So back to how to capitalize on the first year and make it an experience to ensure future success:
1) Take in as much as you can by trying any and every possible experience.
2) Observe the organizational culture and how process are done and how people interact.
3) Lastly, don't feel the need to over step your bounds right away. The people that try to show off in the beginning without knowing the ins and outs of the organization end up reinventing the wheel or offending their superiors.
Be a dedicated sponge your first year, and it will pay dividends as you continue.