(Astrid's POV)
One is to plant seeds far in advance, in the form of prophecies. Because they're created so early, they tend to have gentler, subtler effects. But the trade-off is that they must be vague to preserve flexibility.
You see, no one not even gods or goddesses can predict the future with certainty. We can anticipate likely outcomes, just as a mother might anticipate her child wanting candy or trying to touch a hot stove. But free will is a powerful thing. There are also other gods and goddesses whose actions influence the world, not to mention darker forces at play.
The second strategy is to choose gifted children who can guide others in our stead. But just like with prophecies, we can't always be certain which of our chosen children will fulfill their role best. We hope. We guide. But we can't guarantee. So sometimes a god or goddess will tie parts of a prophecy to the choices people make.
