I was in the same boat 3 1/2 years ago (Wow, I can't believe it's been that long ago). I joined AFROTC as a two year cadet. First, follow the advice of what the others have already said.. But remember, if you come off as just having joined to get a pilot's slot, the other cadets aren't going to take kindly to you.
The cadre at my Det. were very interested in seeing how well you worked with other cadets, and how serious you were with wanting to be an officer above and beyond being a pilot. They wanted to see cadets take the initiative to get things done.
A few specific things that you can do as a two year cadet. 1) Don't use the "I'm a 2 year cadet and they never get the "high profile" jobs. Apply for the jobs in the Det. that you think you can do a great job at and then do it. Don't be afraid to request a leadership role. 2) Do well on the PFT. Get in shape! 3) Do well at Field Training. Although your results may not be in your packet for the Pilot board, it can help in the end. (It did for me) 4) And finally, get involved with your classmates. Interaction is an important aspect that the cadre often look for as far as your potential on AD.
Hope that helps, let me know if you have any questions.. Good luck!