That's an excellent question. Making a NFT that would sell is a tough one. Especially when there are many people looking for "freebies". It's all about airdrops these days. Not sure if anyone would want to buy digital art without getting anything in return. You won't find my creations online, especially when they're truly-unique. Maybe that will attract buyers?
Anyhow, I believe that launching NFTs on a popular marketplace and Blockchain network would help me "kickstart" sales ASAP. I've selected Polygon due to its low fees and fast speeds. If it wasn't because of ETH's unbearable gas fees, I would used it already. Wish me luck!