As I am working through the draft of my novel, I notice how my initial character sketches are evolving. This prompted me to take a closer look at a chapter on character in DEEPENING FICTION by Sarah Stone and Ron Nyren. Stone & Nyren recommend approaching “list-making in a dreamy, waiting mode, not ‘making things up’, but listening for answers that come in their own time” as we write and essentially “tell” ourselves the story on paper in the early drafting process. Stone distinguishes the following essential parts of rendering three-dimensional characters on the page:

1. Physical sensations or appearance
2. Thoughts
3. Background
4. Objects, places that reveal character information.
5. Character’s actions
6. Character’s pattern of speech/dialogue
7. Direct comments by narrator

They suggest using colored highlighters for each category and examining a mentor text to see how much character information our favorite writers include and when and how they introduce it. For my analysis, I added one more detail to the fourth category: the way characters perceive objects and places which I felt was slightly different from perhaps direct comments of such by the narrator which may or may not be the POV character for example.
What may strike you with this exercise was that the categorization isn’t as clean-cut as you may expect. Categories overlap. A sentence reveals background via objects, and/or physical or emotional sensations. Seeing it color coded on the page adds a new level of insight. It is also interesting how the direct narration in a first POV character can (to an extent) pull back to insert less filtered, to a degree objective, information just like an omniscient character could.
This is a valuable exercise no matter what stage you are in your writing journey. Give it a try and see how it serves you in your own writing, to be more meticulous in the choices of how and when to reveal character information.