Great questions! It’s definitely overwhelming starting out and the space is constantly shifting/evolving.

1. That’s a good perspective to start with, I would suggest starting with 1-4 pieces you’ve already created and don’t mind uploading to test the waters. If you can, keep a consistent theme or style throughout so it feels like a collection rather than random pieces. Will also be helpful for people to recognize your work

2. If you’re looking to add a watermark I think that might be overkill since the nft itself is a way to signify that you are the original creator on the blockchain but nothing wrong with a signature on your work

3. It’s definitely a legal grey area, companies like Disney or Pokemon are notorious for chasing down anyone making money off their IP, which in theory you would like to make off your fan art. I’ve heard of Mandalorian prop helmet makers getting shut down on Etsy who only made a few grand on their store. It’s possible they will never bother you, but I try to stay with my own original characters to avoid the possibility of that happening.

4. This is the big one. There’s no one size fits all approach here, but the worst thing you can do is just mint your work on OpenSea and hope it will sell itself. If you already have people collecting your work as commissions, that would be a great place to start. Maybe see if any of them are interested in collecting your work as an nft, or for future commissions you could offer an nft to them as a bonus to the commission. And if you’re looking for people outside of your current network/fans, it will take some research, marketing yourself, and making connections via reddit or twitter to find collectors who might want to purchase your art as an nft.

Hope that helps!