I've seen many people who just graduated from high school or uni asking for ways to get started with tutoring. I was in the same spot after finishing my IB(international baccalaureate)/high school.
What i did was really just brute force it. I wrote an email template giving my credentials and sent it to every IB school in my city. The IB website has a map showing all their schools, and with the schools contact info. It's really helpful if you are also looking to tutor IB students. But I'm sure for other courses similar things exist as well. I would recommend a strategy of sending an email to every school. Wait 1-2 weeks for a response. If nothing, call the phone number of the school.
That worked for me. I emailed about 14 schools in my country and only 1 responded. I got 2 students from that school. Then one of my students put me on to their friends and got another 2 like that.