You can go into training mode and turn on the move details on their side for finding out each attacks. Within the move details should tell you if it's a High P, High K, Mid P, Mid K, etc.
Learn every move individually (training mode w/ move details or movelist), and take note of when you seem to be ducking under/crushing certain attacks (usually indicates a high).
That's about it. Most of the animations are pretty well-matched to their hit level but there are enough exceptions that you can' really on visual cues alone.