I am biased towards anything in the STEM (Science, Technology, Engineering, Math) fields, as those are the skills even basic jobs are going to require more of.
However, more important than going off to college to study is to get involved with people. Get involved in a student organization or seek an internship or volunteer in a field they think they might want to work in. Contact people who are in that field not to ask for a job, but to find out how they got there and what they attribute to that success.
Finally, cultivate skills that, in my view, will be applicable to any field and can make a difference:
- The ability to continually learn and apply new things.
- The ability to listen and actually hear what others are saying.
- The ability to speak and present a topic in front of others (bonus if you can present it in terms that .
- The ability to work with others on a project and meet deadlines.
- The ability to disagree without getting angry or insulting.
- The ability to thank and praise others when they have done something well.