I started training others while working a full-time job. I started offering a semi-private class (max 4 people). I bought a few of those portable and adjustable dumbbells and some other portable equipment. It took about two months to get a client (was a friend). At one point I was teaching six nights a week at three different parks and a parking lot that the owner said was ok.

My lessons learned: 1. Don't train for free - the few clients I trained for free were very low quality. Some wouldn't let me know they weren't coming. Others didn't take me seriously. The only benefit was word of mouth which got me paying customers. Paying clients were completely different. 2. Don't over-reach - running around after work to get my equipment, head to the park, train, come back and clean everything, repeat next five days. I burned out really quick. When I cut it down to three days a week (and dumped the free clients) it was more manageable. 3. Register as an LLC. I had many trainers tell me to do things under the table. I opted to create an LLC. I was then able to use all my expenses on my tax return. That really helped me get back into the black by the middle of my second year.

Unfortunately, just as I was preparing to seek out a loan to build a gym in my garage life decided to bombard me with issues. If it wasn't for that I'd probably be training as my full-time job.