As an academic discipline in the Western world, philosophy is essentially the strategic and disciplined pursuit of wisdom, particularly wisdom about the most fundamental features of the world and human life. We ask the really hard questions and we develop methods for pursuing answers.

What's real? Metaphysics: Space, time, God, immortality of the soul, freedom of will, the nature of existence, the existence of nature, etc.
What is good? Value Theory: Morality, aesthetics, political and social justice, the value of lives and ways of living, etc.
What is it to know? Epistemology: Ways of knowing, possible objects of knowledge, certainty and fallibility, consensus and dissent, etc.
By what methods can I become wise?

(See epistemology!)

Logic: Sentential and predicate logic, multivariate and fuzzy logics, non-deductive inference, fallacies and biases, etc.

Narrative: Storytelling, first person perspective-taking, immersive imagination and fantasy.

Thought experiments: Controlled experiments in thought when we physically or morally can't do the experiment in reality, e.g. the trolley problem, Mary's room.

Experience: Pain, acquaintance knowledge, interoception, qualia, phenomenal experience.