What does the phrase Good on you mean?

Saying good on you, the speaker indicates that the addressee has displayed, in a conspicuous way, an attitude which the speaker assumes both she or he and the addressee admire. . . . in good on you, the stress is on people's potential, on what they can do, rather than on what they have done, and on the kind of person ...

Do good to or do good for?

Doing good to someone means that they are the direct recipient of the benefit of your action. For example, if someone is hungry and you give them something to eat. Doing good for someone means that they are an indirect recipient of the benefit of your action.