It's a much experienced pitfall: timing. When working on an animated video, you're so absorbed in the project, that you might lose grip on how outsiders will see the result.
Optimize timing to make your animated video stick
You've researched and contemplated, you wrote the script, you know which graphical objects to use, which words to write, and above all, what message you want to convey. That's great! But what about your viewers? To your audience, everything they see in your animated video, will be new.
As you create your project, you see your video or presentation hundreds of times. You probably know it by heart by now. Your viewer, in most cases, gets to see it once. So it's in your best interest to make your clip in such clear fashion, that the message sticks.
One thing that can help you achieve clarity, is timing.
In short, give your viewers the time they need to read, understand, and remember the message.
Avoid big chunks of text
In a fast-paced visual world like ours, showing a screen-full of text is hard to get away with. There is too much information, of seemingly equal importance. There are fast readers and slow readers - how will you decide how much time it takes to read something? And is reading the same as understanding? And what about the (majority of) viewers who skip reading big chunks of text anyway?
Best break it down to bite size bits. Put emphasis on the more important bits by giving them their own space and, indeed, time.
Allow time to see
Flashy fast-paced sequences of images and/or words may work well for music videos and the likes, not so much for clips that mean to convey a more resonating message. Remember that your first-time viewer will have a lot to take in. Showing a picture for half a second may look dynamic, it usually is not very helpful in terms of clarity.
The hand-drawing and handwriting animation presets tend to act as a double-edged sword here. One might assume the time taken to draw/write is enough to let the viewer "get" what is being shown; though it's safer to state that the screen time of any object actually starts when the handwriting or hand-drawing has completed.
Always allow for objects to be seen at least a second (preferably more) after the initial buildup.
Also, remember that most people will need more time to get a message, than simply the time they need to read it. Let it sink in.
Guide your viewers' attention
Much like a painter needs to take a few steps back to get a clear view on what he's working on, so should you.
Try to watch with a naked eye - i.e.. as someone who watches the video for the very first time. Is the message clear? Can it be clearer? Moovly offers plenty of bells and whistles, and it might be tempting to use them all, at once. Imagine seeing a video where all kinds of different stuff is happening at the same time - you wouldn't know where to look first.
So, guide your viewers' focal point. Add highlight effects, use pop-ins and the likes, at logical time intervals. If your animated video is based on a voice-over track, you can take the timing from there. If you're working with a music track, you could choose prominent beat hits to mark emphasis on graphical objects, or words.
In equal measure, objects or words disappearing from the stage act as attention-grabbers as well. Be mindful about when, or how, you stop showing any given element.
Rewind often and try to look at your video or presentation with a fresh mindset. When your clip is ready, show it to someone nearby and check if they got the message. If your test-audience "gets it" the way you intended, you're good to go. If they missed something of importance, you'll know which area to fine-tune.
Case in point:
Most viewers will skip reading this lengthy collection of words (and I don't blame them) anyway, so here's the gist of it, in a Moov!