1. There will always be a locked door.
2. Even if there's a knife or anything that could be used to stab and kill the antagonist, the protagonist will not pick it up and will use a less useful object instead.
3. There's almost always something useful in the library.
4. If there's an incinerator in the game, you will most likely use it to burn the antagonist, but you probably either have to do things to get it to work or go through a huge amount of trouble just to get to it.
5. In-game characters seem to have the habit of leaving notes filled with secrets for the protagonist to find.
6. When a statue or human-like object that used to be there suddenly disappears, it's probably gonna show up and chase you.
7. There's probably a secret passageway in the fireplace.
8. If it's a shiny object on the ground, it's probably useful.
9. It ain't a proper RPGmaker horror game without a chase scene.
10. When stuck, examine EVERYTHING... and save in between.
11. Being able to save the game anytime is a wonderful thing.
I'll add more to this if I think of other stuff. xD