The Belldandy effect
There is actually a word in Japanese for her particularly set of characteristics- "kirei". Translated literally, it simply means "beauty", but there is a deeper meaning to the word when used in the context of describing a woman- something along the lines of "gracefully feminine". In the series, she is described by others as someone who brings calm and serenity to an otherwise tangled world. Her entire existence in the series focuses around using her powers to help those around her, with her attentions focused at all times on making Keiichi happy.
And interestingly, the very fact of her presence in his life makes him happy- to the point where his happiness is so great that the attempts by Belldandy's demonic rival to make him unhappy completely fail.
- Take time and care over their appearance;
- Grow out their hair and maintain it;
- Learn as many domestic skills as possible;
- Improve their minds through reading- and I'm not talking about the modern chick-lit trash that passes for "literature" these days;
- Be pleasant sources of quiet serenity;