Can you elaborate a little more on your question? If your question is about marketing small group training, you could always place an ad, make flyers, hold demonstrations, tell your existing clients, etc… Word of mouth is wonderful if you have a following.
If your question is about teaching small groups, it’s very rewarding. You are able to teach a class, yet focus on the individuals. There are numerous classes you could do (I teach TRX and bootcamp classes this way) to keep it interesting and challenging. In addition, it can attract more clients who want individualized training.
Small group training can be a lot of fun. It’s also less expensive then 1-on-1 or 2-on-1 and there is always the support form the others in the group.
For marketing you can use various ways such as the word of mouth approach, go to networks around your area and promote your class, offer it as a deal into one of the daily deals in your area (such as Groupon), offer a free class to who ever would be interested taking the class, do a press release, post it on Craigslist, post it at your web site or FB and/or offer something so unique that people would be attracted to your class instead of going to a similar one in your area.
I hope this helps.
Identify who you’re targeting for your small group: weight loss, women, sport specific, etc. then market to where these people meet up.
Let your current client base know that this is a new offering and offer a referral “reward” for those who sign on. Free sessions work great!
Of course FB, social media is another great way to get the word out.
Identify what makes your small group different and why people would want to attend.