Take outside help: As I knew next to nothing about my child’s area of interest, I spoke to a few people and set up a couple of meetings for my daughter. This helped to give her a realistic picture of what she could expect from her career.
Think of ways to ascertain interest: Many children do not have the exposure to really decide whether they are passionate about a subject while they are in high school. So they often simply pick subjects they do well in. No harm in that, but it may also be good to explore further by organising internships with friends/ family or asking the child to do a summer project by choosing a topic from the area of interest.
Do your own research: One of the challenges that parents face today is a lack of understanding of the choices available. As your child approaches high school, become well-informed yourself by talking to people and reading a lot. Assimilate what is before you so that when the time comes you can actually facilitate the process.