Although most babysitting is still performed on a very casual basis, if you’re going to be performing this service as a business you should protect yourself from liability. Your best qualification is your reputation in the community. A young person should be able to offer references from teachers as well as parents they have helped previously; older people should offer references from happy clients. If possible, visit the home and meet with the parents and the child before you take your first job as a babysitter; this will reduce the surprises for the child and for you. Make sure you know the rules for yourself, as well. Are you welcome to raid the refrigerator, or are you expected to bring your own meal? Do the parents expect you to clean up after the children eat?
To get started on this job, you can post flyers in schools, community centers, and supermarkets. Place ads in local newspapers and shopping guides. Ask family and friends to spread the word about your availability. Send letters to the human resources departments of major employers in your area. Do the same with school nurses. The principal up-front expense is for advertising and promotion.
There is usually a standard rate for babysitting in your area. You can add a premium for emergency calls and for jobs that continue late into the night. If you are making yourself available to care for a sick child, make sure it is clear who is to pick that child up from school. Most schools will not release a child to anyone but a parent unless they have written authorization.