Look out for:
- One frame of black between shots.
The snapping tool is your friend, friend. You'd be surprised in QC how freaking often it is that we find a single black frame between two shots. And if we miss one of those you just know a distributor will kick the movie back to us to get fixed. Be careful out there.
- Speed changes in the timeline.
This is about the number one thing which ticks off our distributor(s). If a piece of footage really needs to be at a different speed, it has to be brought into AfterEffects and the speed changed there with proper interleaving of frames and suchlike.
- Continuing the same shot as a new segment.
I know, you match-framed the shot and you just want to add some more time to it. But instead of it being one segment, this shot is now divided into two segments. Don't do this. There are a couple reasons not to do it: one is that you've just made two things to color-correct rather than one. The other is that now there's one more thing to get bonked out of sync. Sure, it barely ever happens -- probably just twice in a feature. But that's enough to fail QC.
But, you think, what if I'm changing the speed in one of these segments? See the rule above, brother, see the rule above.
- Embedding in embedded sequences.
I don't know why, but FCP and Premiere start to get very cranky when you've embedded in embedded sequences. Also, it makes it vastly harder to go back and see what the footage involved was originally named. Especially for the post-production-sound department this can be a hassle. But more than that I've found that both Premiere and FCP become very obtuse about correctly rendering out sequences-within-sequences. It'll look at first like it rendered out properly. But your distributors will find that the program did some unholy thing when it rendered out your footage with too many layers of embedding.
Try to just use the actual original synced footage when you're putting scenes together into acts on a sequence in the timeline. My angina will thank you if you do.