I think as a developer you have to look away from your own opinion of what your game is worth because it's irrelevant, instead look at what people pay for games like yours as well as how much they sold (using steam spy and similar services). You need to find games similar to yours and ideally with around the same marketing, you'll never be able to predict how your marketing will work out but it will give you a better idea. If you find a few of these games it should give you a rough estimate of the price elasticity of demand for games like yours. This shows you how many people are willing to pay what prices. For small casual games without a big budget you'll probably find the highest players*price at around 2-4usd (at least for the type of game I was looking at at the time). So take that number as highest predicted revenue and then also take into account if you would like to undercut the market to get more players with lower revenue.
If you are releasing a game semi-professionally I would recommend this route. Take it with a grain of salt though because the game I did this for didn't get made in the end because we didn't think we could make back what we would spend developing it and for the game I developed as a hobby I just wanted as many people as possible to play it so I released it for free.
For small hobby games I like the pay what you want model but I don't want to try and make people judge the worth of a game from screenshots before they try it so for my own game I left it free to let as many people as possible play it (I know people could enter 0 as the amount but personally I would rather not play a game than enter 0 in the amount field and download it. Just makes me feel guilty.). If it were possible I think the greatest option for short hobby games would be a message on the download page that says the game can be played for free but it will ask you to pay how much you think it was worth at the end. It might be idealistic but as a developer and a player I would love if the amount paid reflected how much the player enjoyed the game, not how much they expect to.