How to sell a niche product on Amazon realisticly

I’m really into the outdoors and backpacking and want to sell the gear for that niche . What should be my expectations? I have a few ideas that would be hand made or more custom order at a prime rate. I’ve tried to sell before but nothing happened. Any legitimate courses anyone would recommend? I have a successful HVAC company and it’s growing but I want to build something on the side I could potentially be remote . Any tips?