How can you identify the first person point of view?

If the piece is written about something "You" is doing.

E.g "Last night, you dreamt you went to Manderley again. It seemed to you that you stood by the iron gate leading to the drive, and for a while you could not enter for the way was barred to you. Then, like all dreamers, you were possessed of a sudden with supernatural powers and passed like a spirit through the barrier before you"

Since it's an odd way to write ("who are you to tell me what I am doing?") , it tends not to be used that much except in adventure game-books such as the Choose-Your-Own-Adventure or Fighting Fantasy, where the reader has some control over the direction of the narrative.