-Knowledge of one's own character, feelings, motives, and desires
-Knowledge of one's strengths and limitations
-Detailed knowledge of ones own likes and dislikes
-Knowing when one is stressed and what the cause is.
-Ability to know if one will like or dislike a situation before being put into it
-Knowing what one wants out of life and actively pursuing it
Overall I'd say the types that excel most in these areas tend to be the IxxJ types.