Another way is to look at YouTube channels that focus on Amnesia gameplay. Many of these channels will play through different custom stories and give their opinions on them. This can give you a good idea of which ones are worth checking out. For example, if a channel has a high - engagement video on a particular custom story, it's likely a good one. Also, some gaming websites might have curated lists of the top custom stories based on user votes or their own reviews.
First, you should consider the popularity of the custom story within the Amnesia community. A story that has been widely discussed and recommended is more likely to be a great one. Second, look at the reviews and comments from players who have already played it. They can give you insights into the quality of the story, the gameplay mechanics, and how scary or immersive it is. You can also check if the custom story has won any awards or been recognized in any Amnesia - related competitions. This can be a good indicator of its quality.