In Guangzhou, according to the labor law, minors who are 16 years old or older can do some specific types of part-time jobs. Here are some part-time job options for minors aged 16:

Convenience stores and supermarkets: Some convenience stores and supermarkets may employ minors aged 16 or older, for example, as cashiers, shelf organizers, or store assistants. You can check with your local convenience store or supermarket to find out if there are part-time job opportunities.

Food service workers: some restaurants, coffee shops or fast food chains may accept minors aged 16 as waiters. This may include serving customers, serving food, cleaning jobs, etc. You can check with some reputable fast food chains or local restaurants if they have relevant part-time opportunities.

Tutoring or tutoring: If you have some expertise in a particular subject, such as math, English, or music, you may consider becoming a tutor or tutor. You can talk to educational and training organizations about part-time opportunities or advertise your tutoring services around your school or community.

Please note that the reason brick-and-mortar job advertisements state that they require employees over the age of 18 is because some jobs may involve some legal and regulatory restrictions, such as working hours, work intensity and safety requirements. Policies and hiring conditions may vary from business to business, so it is best to check with the specific employment agency or employer about their requirements and policies.

In addition, it is important to ensure your safety and legal rights regardless of the type of part-time work you do. Before accepting a part-time job, make sure you understand the job content, working hours, remuneration and establish relevant contracts or agreements with the employer, and comply with relevant laws and regulations to protect your rights and interests.