Answer:
If you want the game to be "hard" be paranoid. If you are not scared, this game is simple. All you have to do is check your camera to pirate's cove to see if foxy is there. Otherwise, check the halls on your left and right. When Bonnie and/or Chica come, quickly close your doors and wait till they go away. Then, on night five, check the stage to make sure freddy has not moved. Night 5+ is the only real challenge.
Step-by-step explanation:
My Strategy
Rythm is essential to surviving all the nights at Freddy Fazbears. Here is what I do.
First, check the light on the left.
If anyone is there close the door, or keep the door shut
If not, or after you have closed the door, move on to the next step.
Then, close the right door*.
Check the camera to make sure foxy has not moved.
If Foxy has moved, quickly shut the right door and check camera 2A. When your are pulled out of your camera, return to your camera and check on Foxy.
Check the right hall light.
If anyone is there close the door, or keep the door shut.
If no one is there, or you have the door shut, repeat all of these steps