When considering (for example) a two-person interaction, involving you, choose your actions as if you might be magically turned into either of the participants.
This concept is alluded to by JohnRawls' TheoryOfJustice.
Is this realistic or even possible?
It's something that, to some extent, we do routinely and intuitively. "Put yourself in my shoes", "I wouldn't do that if I were you", "I'd do the same in your situation". When considering a play in a game, it's a common tactic to ask oneself "if I were the opponent, where wouldn't I want me to play?" It has even been suggested that there is an evolved, biological basis for the brain's ability to process such questions (and arrive at correct answers).
I think it is more fundamental. No communication can take place between parties unless each models the other in some respect.
Or in other words: "Do unto others as you would have them do unto you."
Vaguely related, from a "see things from the other guy's eyes" perspective: Several years ago I was trying to teach chess to a small number of variously aged persons, and found that one of the hardest things to teach was "thinking from the other player's seat."
My solution of the day was to have each player move the opposite-side pieces. Fred has the White pieces, Rusty has the Black pieces, from the White side of the board Fred plays the Black pieces, and from the Black side of the board Rusty plays the White pieces. I dreamt up a cute name for it, and I don't even recall what that was (maybe "ReverseChess?" or something).
It achieved the desired results. After several days of playing the other fellow's pieces, you could anticipate the other side's moves. In fact, there were some amusing moments as they got used to playing their own pieces again.
It would be interesting if there were some tool of this kind for "playing life" where you make the other guy's decisions and live with the consequences. Haven't found one yet.
"Let the one cutting the whole into portions for others be the last to take his own portion" -- anonymous