For this set there are many things that give it a sense of movement.
1) The birds in the sky with their wings positioned at many odd angles, it makes them look like they are actually flying.
2) There are some ripples in the water that helps to add to the appearance of movement within the set.
3) Swirls in the sky make it appear that there is wind there and that adds to the movement.
4) The unicorns appear to be moving because of the way that they are holding their hooves, up out of the water like they are going to walk forward. Then the slight ripples around them helps add to that impression.
5) The girl and the waterfall give the impression of movement, by the odd angle at which she holds her arms as if to catch the water as it falls. The streaks and sparkles help make look as though it is pouring down.
6) The girl on the deck looks like she is walking because of the angles her arms are at, like she is moving them as she walks.Then there is the way that her upper body is twisted away from were her skirt is laying like she making a turn.
7) Lastly the girl in the sky looks like she is flying because of how she is holding her arms out behind her; how she is leaning forward as if into the wind; how her hair and clothes are dragging out behind her.
I would really appriciate a critique @justjules2332 thanks. :D