I'm starting a new label called Quick Tips where I can add simple little suggestions to help you with your animation. My first one is about animating lip sync.
When your animating mouth shapes it can be quite fiddly (depending on the rig) making the transition from open mouths shapes to closed mouth shapes. And seeing as how opening and closing our mouths is what we usually do over and over again when we talk, you can find yourself playing with the face controllers to reproduce the same action until your ready to pull your hair out.
Sometimes what I do is make two keys before the dialogue starts one with a generic open shape (a kind of "Aaah" shape) and and then one on the next frame with a generic closed shape (usually an "Eeee" shape because I find it most common). All the mouth shape controllers should be keys on these frames.
With the mouth shape controllers all selected I copy the key for the open mouth shape. If you made the closed mouth key second then the mouth should be closed through all of the dialogue. Scroll along scrubbing the sound until you find the first sound that will require a closed mouth, set a key, scroll along until you find the next spot for a closed mouth, set a key. Go back to the point between the two mouth shapes where the mouth will be open (assuming there is one) and paste the open mouth key. Work your way through the dialogue setting keys for the closed mouths, then going back and pasting the open mouths where need between them. Now you have a rough pass on the mouth animation that took very little time. You can playblast to check the timing.
Now you can go back and start fleshing it out with more specific shapes for the specific sounds and mor keys where needed.
Remember to make the sound with your own mouth, say the whole word. I can make an "EEE" sound with lots of different mouth shapes. You have to find the right one for this word, emotion and character.
Playblast your work lots and watch it over and over. This actually saves you time, trust me.
Hmmm, well I was hoping that quick tip would be a bit quicker. But there you have it :)