J.F.
I tutor privately and started by advertising every where.
School level: contact each school principal and have your less than 1 minute sales pitch ready. You may want to ASK to come to the school to meet with the principal over the summer (the least busy time of the year). Be ready to offer your workshop in the fall during teacher development or through the summer to teachers willing to take the course on their own.
Community level: Prepare WELL WRITTEN fliers/brochures that can be copied nicely at office supply stores and distribute them at the libraries, book stores, daycares, etc. (any where that your target audience's families or teachers visit).
Have nice business cards made (try www.vistaprint.com).
Hit the beat and make the phone calls. Know what you are offering before you offer anything.
Advertise on craigslist and www.care.com