I’ve been a group ex instructor (in mumbai, India) since the last 16 years teaching a cross training class (aerobics, step, tabata, bootcamp, etc). While my classes bring in an average number of people, i would like to reach out to more since i have so much to offer in terms of knowledge and experience.
There are many ways to market. I think there are a few basic ideas to start off. First: schedule in a block of time to sit down and think through your strategies. That is much better than doing it piecemeal. Second: Identify your budget. Advertisers will paint glowing pictures of how much business they will get you, but remember that they want to sell you something. Advertising can be useful, but also can be expensive, so you want to use it wisely. Talk to some people in your field, or do some research to see what venues people in your business use most widely. Third: Figure out how much time you will spend on this. If you use social media, for example, it can be very cost effective, but it also will take time that could be spent on the floor making money. It is as important to budget your time as your money.
In terms of social media what you use should reflect what the population you wish to reach uses. I use Facebook, but not twitter, but that is a time allocation thing. I know people who use twitter to great effect, I just do not want to add another thing to do right now. If you have an email list of current clients a newsletter can be a good way to reach out.
Offer deals to your existing clients: Bring a friend to class for free day. Buy passes with a friend and get a discount on both passes, for example. The number one method of getting new students that I have found successful over the years is word of mouth.
I do not know how your school system works, but I have taught after school programs at our school. I find in a small community if the kids know you they will talk to the parents about the class. And middle schoolers soon become high schoolers, and older kids are possible students.
Volunteering is also a good way to get known. I have a friend who recently volunteered with a huge yoga event and got some great press.
Press like an article about your business is MUCH better than press like ads for which you pay.
These are not an exhaustive list, but a few thoughts off the top of my head. I am sure if you let yourself get creative, make a plan, and stay positive about the value of what you have to offer you will find things open up.