Job Shadowing is an excellent way to learn about the daily responsibilities of professionals currently working in a career field of interest.
Completing a Job Shadow during winter break will help you to utilize your time in a productive way as you are able to learn and observe what typically goes on on a daily basis in a particular career field. Jobs that you may think are exciting and fun may turn out to be the most boring job you you ever could imagine. On the other hand, you may find that the experience excites you and gives you the information you need to make an informed career decision about a career field you explore and really end up liking.
A good way to do job shadowing is to check and see if your college offers a Job Shadowing Program. If not, consult with a career counselor at your college to see how you can access college alumni who may be interested in sponsoring a student for one or more days during winter break.
Whatever the result, you will definitely know more about a career or industry once you've spent some time observing and getting your questions answered.