Corridor Crew (a small VFX team with a long history on YouTube) have made a couple of videos on identifying AI generated video. Start with this one for example.

The points that I can remember are:

1. AI tools can’t generate more than 10-20 seconds, if you see an unbroken shot longer than that, its not AI.
2. Check for consistency between shots, this is pretty hard to do with AI. E.g. if the same person keeps appearing with similar, but still different clothes, its probably AI.
3. Visual artifacts, especially in the background can be a good tell.