You can do just about anything you want as long as it is productive.
You're right in that you are starting early. I would be sure to focus on your grades. You could also study review books to help give you a head start for step I. Blowing step I out of the water would be a nice plus in your app; although, it may be a bit premature to be hitting a bunch of review books since you haven't had the classes yet (guess that's up to you)--some people do like to start early.
You don't have to limit yourself to only medically related activities. For anesthesia this is a big plus. The programs I interviewed at loved talking about the things on my CV that made me different from other applicants. For example, I started my own business during med school, and I was asked about it at every interview. It showed a side of me not related to medicine that most of the other applicants didn't have. I'm not saying that you need to start a business, just keep in mind that whatever you do may not necessarily need to be directly linked to medicine. Have fun and find something unique that you enjoy doing.
If you do research, it helps more if you get published (of course), so try to pick something that will lead to a presentation or to getting you published. Be sure to do something that you enjoy and that you can devote time to in order to be sure that it is done right. Don't just do research to build your CV. Being a lab rat with no real purpose behind what you are doing won't really stand out on your CV all that much anyway. If you do research, get to know your mentor. Mentors can serve to guide you as your medical career develops. One of my closest mentors was someone that I did research with who took an interest in me and aided me throughout medical school. Whenever I had questions or needed advice he was the person that I went to for help.
Some of the things that interview comities look for are 1. Step I score, 2. Letters of Rec, 3. Grades, 4. Extracurricular Activities, 5. Research/Publications 6. That you interact well with others (your team/patients) they will get this from your Dean's letter which will summarize your clerkship evals.
Be sure to focus first on your classes at this early stage. You can branch out as you get a handle on things. Have fun, work hard, and good luck.
