Qualifications
To get your first job in this industry, a degree or certificate of some sort that backs up your knowledge of all things sound would be a good jumping off point. You also want to demonstrate good social skills, as any employer will be looking to you to present a good face for the whole operation, and you'll need that salesman charm to secure gigs.
The earlier you start working, the better. Nothing speaks louder than experience. Except that sweet audio you churn out. Make sure to have samples available.