Same thing on my end. I get a random sale every few days but I agree everyone is probably holding off until the Winter Sale. I'm getting more wishlists post release for some reason. I'm hoping (fingers crossed) that I can pickup some sales every time the game goes on sale. But as you said, it certainly isn't paying the bills...or any bills for that matter haha.
I'm still mulling over what to work on next. I have a few ideas and obviously it would be inadvisable to try working on all of them all at once.
A big part of me just wants to dive into making a retro dungeon crawler. I know I'd never get tired of it but I don't yet have confidence in my ability to create inventory, character leveling, and turn based combat systems.
On the other hand I've been sitting on a single player card game design that would be fun and less monumental. I've also got an action-arcade game idea that I'm confident I can make well but feel it isn't really pushing me to learn more.
Have you zeroed in on what you're going to work on next?
As for what I've learned...
Whatever the project it needs to be something you'll passionately work on for twice as long as you think it will take. That last 20% is dangerous territory!
The other big think is to get that game out and playable in some form as early as possible. Not just for testing but also to start marketing. The only pitfall I can't get around here is that some genres just aren't built for an extended lifespan! I don't want that to drive my choice of genre though. I'm getting really tired of everything being a roguelite or loaded with crafting busy work.