It's been slow for me to find the right niche for me but over the past year, I have been consigning scrub caps and stethoscope covers to a local hospital shop. Not many are willing to accept consignment items and don't seem to want to buy outright so I guess I just got lucky. I do pretty well with that.
People who know me have approached me for memory quilts or baby quilts. I give them a good price but still make some money for my labor.
I also seem to do pretty well with accessory items - wallets, totes, eyeglass cases, phone cases, things like that.
You run into people who want to bargain with you so you have to decide if you want to raise the price a little so you have room to come down in price. That also creates repeat customers because they think they're getting a deal from you as well as referral customers.
You will also run into people who appreciate the work involved in a custom item and will pay a fair price (so they pay the higher price without question). I recently made a bag for a repeat customer and when she picked up her latest bag, she gave me more than I asked.
I don't make a living at this because I'm on disability and can't sew everyday or promote myself as I would like, but it definitely supplements the income (and my fabric addiction). :-)
Hope this helps. Feel free to PM me if you have specific questions that I might be able to answer.