Make sure you don't cover the camera or microphones with your finger. This can ruin your whole project if you don't have good footage.
There isn't too much footage. When recording footage, it is always important to get a lot. That way, if something turn out to be bad, then you have a backup.
Hold the iPad from the bottom corners. This makes it easy to grip, as well as it doesn't cover microphones or the camera.
Give the subject space to talk. When recording footage, make sure that if the camera is on the right side of someone, they are in the right side of the camera. This uses the rule of thirds. If your subject is looking at the camera and standing in the center it looks very awkward.
Those are just a few tips.