Real truth
Truth is better than realism.
Improv as a stage art form allows us improvisers to do almost anything we want. All too often however, we limit ourselves to overly realistic portrayal of our characters and their lives. I think it might be because of an overdose of television and movies we are consuming, making us forget the power of theatricality.
Make it bigger! We should use all of our body and voice to deliver our message to our audiences. Think of the stage as a canvas to paint on rather than a set to play in.
Dance! Sing! Bring us inner monologues! Jump around! Lose yourself completely in dilemma's, emotions and beautiful moments. Go for choregraphic gestures to engage the audience into the inner world of the character.
Use everything you have to portray the truth for your character and don't let yourself be limited by that dirty thing called realism.