Take your time in combat. It is not about speed, but precision.
Think outside the box when you encounter a clue. Sometimes it’s simple and transparent. Sometimes it's not.
Don't rush into buying the first thing you find in the shop. If you save up some money, you'll later get a chance to buy some much better items.
Grab a pencil and some paper and name the doors with short descriptions. Use this note to remember where you left the tools or weapons and which door you need to open to save up on some time.
According to some players, you should disable auto-brightness to be able to enjoy the game to the fullest at any time.