Becoming an expert in data structures is... not of much value if the thoughts you want to express are all muddled. -- William Kent, Data and Reality, 1stBooks, 1998.

Consider the key topics: existence, identity, attributes, relationships, behavior, and modeling.

Existence: Is cogito ergo sum sufficient?  To what extent am I really present and engaged in the process of life around me?   How real are the physical things I experience?  To what extent do I exist in some spiritual realm independent of the physical context?

Identity: The old "Who am I?" bit. What is the true nature of the kind of person I am?  What sorts of needs, goals, outlooks define who I really am?

Attributes: What kind of person am I?  What are my values, my assets, my limitations?

Relationships: This is the core of it all. What is the quality of my interaction with parents, lovers, spouses, children, siblings, friends, colleagues, and other acquaintances? What are my connections with things material, social, spiritual, and otherwise? What are my needs here? What are the issues and problems? How can they be improved?

Behavior: What should I plan to do in various situations? How?  What might be the consequences, both intended and otherwise? What contingencies need to be anticipated?

Modeling: How accurate and useful are the constructs I use to explain all these things? How effective are these kinds of explanations in helping me change what needs to be changed?

The above is from the preface of the 2nd edition of Data and Reality