MN8 is a notable sutta that has a long list of skillful qualities, forty-four to be exact. Here is the first:
MN8:13.1: Cunda, I say that even giving rise to the thought of skillful qualities is very helpful, let alone following that path in body and speech. That’s why you should give rise to the following thoughts. ‘Others will be cruel, but here we will not be cruel.’ ...
I have found this list extremely practical and it requires no deeper knowledge. Indeed, the sutta remarkably starts out emphasizing that meditation itself (and therefore the deeper insight thereby gained) is separate from the exercise and practice of the listed qualities, the practice of self-effacement. Ethics, wisdom and immersion are all required. They are the three practices. MN8 directly addresses details of ethics, of skillful qualities.