You can hire additional trainers if you’ve established a brand for yourself and take a percentage of what they earn for helping them grow their training business – this is all if managing and working with a team is an option for you.
Partner and Group training are great solutions both for you and to open up to a new layer of the market or retain clients who might have reached initial goals but want to continue with you and like the idea of lower rate but continued accountabilty.
Products. You can either work as a dealer for some specific companies making a small percentage for sales of equipment you might recommend to them. Or come up with your own: a workbook based on a formula you use with clients, a niche that you have already but haven’t explored. An e-book is something low cost to you but brings in passive revenue to you any time. A logbook for clients to use that might include nutrition, activity, etc the possibilities are endless. If they love you they might just love your product for themselves, their friends and their relatives.