A philosophical approach to ethics brings in many considerations that may initially seem remote from the question of what to do, but can greatly enrich our ability to think about it.
Philosophy is not just any view of the world, but an inquiry into the meaning of things that is sustained and free. It also could not be the activity of an isolated individual. It is an intrinsically historical development, because it is a cumulative achievement of the virtual universal community of talking animals across space and time, through various ups and downs. The best way into it is through a kind of dialogue with the great philosophers. Pursuing this in depth turns out to involve many historiographical questions.
Truth does not come to us ready-made. What we take as truth is always the provisional result of a development. The primary activity of reason is the determination of meaning through a kind of open-ended interpretation. It is therefore involved with a kind of hermeneutics.
Ethics involves us as whole beings. Subjectivity is manifold. Its ethically important aspects have to do both with our acquired emotional constitution and with shareable contents and commitments.