For tutoring - decide what ages and what your charges will be, think of a business name and then make a business facebook page and share on local mums groups/community pages. Also remember to register as self-employed with HMRC. Register your current school dbs with the renewal service so you don't have to get a new one too as that is tricky if you are self-employed. You could also join a tutoring agency to get started and build up your name in the local area.
Thanks for your replies. I haven't registered yet no, I'm just waiting to find out if I'm going to be made redundant from my current job due to Covid. I would really like to do tutoring as I am a teacher, and could do it online (due to social distancing) but I'm not sure of the best place to advertise. :-)