Broadly, this is how you can approach the task
Identify your child's interests
This can be achieved in two ways. Begin at home by talking to your child about his/her interests, likes and dislikes and how some of these preferences can translate into a more serious and long-term career option. At this stage, let the child decide his/her preference even if it's unconventional rather than force your own choice on your child.
Next speak to your child's teacher or tutor or school guidance counselor for a more formal assessment of his/her talents and interests.
If both methods reveal something common you might be onto something constructive.
Get more information on careers
Let your child take the lead in gathering information and data on his/her career interests. This should include growth potential and development in the career. At your level you can connect with people long associated with that career option. You can talk to them on whether they can help place your child to get valuable work experience.
Set goals
Identifying a career is just the starting point. After that there are a whole lot of steps to be undertaken so that your child does not get lost along the way. It helps to break the journey down into primary and secondary goals. For instance, a student studying for chartered accountancy must first get placed in a reputed chartered accountancy firm with specialization in an area of his/her interest, be it income tax or audit or consultancy. This is the primary goal. The secondary goal is to clear the exams on schedule so he/she can kick start his/her career as planned.