I've notice that a lot of new mappers just doesn't spend much time on the storyline nor scares. They create their maps, say "You must escape the castle", add some silly naked guy jumpscares and that's it.
I created a steam guide for Amnesia mappers. It's based on my own and a majority of reviewers opnions here at moddb. I'm giving hints about how you build up an atmosphere, why you shouln't overuse jumpscares, tips about what kind of quests you can add and so on.
If you wanna take a look, here's the link to it:
Feel free to leave comments here or at the guide page what you think about it ;)