I hired the smartest juniors and seniors at my high school to tutor K-12 kids in their area. We started at Highland Park High School and expanded to one other school.
I hired one student every year to run and manage the service by using a web system I designed. Clients would book their sessions online and tutors confirm the ones they can make it to. This takes about 90% of the work out of scheduling.
Since I was planning to expand from early on I built the system in a white-label fashion so that I could run everything on the same database and only have one code repository.
I shut down the service once I felt that I couldn't pay enough attention to it to keep things running smoothly.