Hi TCA - I am currently applying to plastics now, and I remember asking my dean the same question when I was a first year. Here is what he told me, and what I can now say was very helpful:
1. Study. If you are at a school that has AOA, you should aim for it - for many schools that means being in the top 10% of your class. You should aim for >240 on step 1.
2. Research. Start talking to the plastic surgeons at your school about research projects they have, and get involved. Your #1 priority needs to be grades, but try to get on a plastics project during the summer between your first and second year. Posters and presentations are good, papers are better.
3. Consider if/when you want to take time off. Lots of medical students do this now. This is more important if you have a limited research background, or if you have a weaker plastics program at your school. It's great to get publications, meet people, and get letters, but not every one needs the year off to do this. There is an entire forum on SDN about taking a year off as a medical student.
Other than that, relax and enjoy first year!!
