hey thanks a lot!, it's really no one easy answer to that. for me there are things im following and it sometime works sometimes not. i've been doing this for too long and there are things that ive noticed.
- the thumbnail matters, it needs to show what kind of game it is and a bold but still themed title.
- people like consistency, if your art has different artstyle from each object inside the game it'll looks unprofessional.
- marketing your game logo and making it feels special by accentuating it at the very start of the game load out, seeing godot logo makes it looks like you're still practicing.
- people only will gives you 5 seconds before leaving your game page, before they even click it, they will hover the gamepage and 2 screenshot pop-up if those screenshots are static they might think that you didn't put any thoughts into it, try putting gif instead with much motion and best cuts that you can record out of your game. itch only allows you 3mb gifs so try to cut down to only 5 secs. with a very compact information of what your game is about. and if the file is still too big you can compress it online sites. try to put atleast 5 gif screenshots.
- beautify your page site, try to learn html coding to have more pop on to your page. and along with it try to do some art uniquely only for the page. and some other miscellaneous effects like hovering effects, maybe even gradient motion backgrounds. as long as it has the same vibe and feel of inside of your game.
hopefully this'll work on to your next jam