I don't use prophecies much, but I was able to recount how I had just started a story that opens with four different characters foreseeing their future because it was the New Year. Another panelist asked whether it was the same way, and I explained that two used the old-fashioned way, where magical stones are used to detect influences, like a compass needle points north, and two invoke spirits. One character told another that the stones are stupid and don't know much, the other flung back that the spirits could lie -- another panelist asked me if they did lie, and I said, by omission, which is where we dived off into how prophecies can mislead your characters and readers.
And really ought to. On one thing, we all agreed: prophecies, like any form of foreshadowing, have to surprise you as well as satisfy you that they've been fulfilled. And there's the substitute for motivation, which does not work well. I brought up the Belgariad, one panelist had hoped to avoid this, and I pointed out it was the prime example of a prophecy instead of motives. We tossed that about a bit.
Prophecies can also generate conflict by trapping you in something
Then there's the difference between forecasting and full-blown prophecies. When you are trying to see the influences and the present time and what they will lead to, they can misled you -- you can even see something the next day that's different than the day before. On the other hand, when the oracle lays it down, it needs to be true, even if very misleading. Or so I held. Other panelists were less convinced, but they did not convince me that it's not like an unfired Chekhov's gun.
At one point we discussed our favorites. I was the only one who had one at once: The Horse and His Boy. If you remember, the prophecy only gets revealed after the fact to the main character. Another liked Oedipus Rex.