I mean in terms of drawing it was quite good,to improve it I would make the movements look a bit fluid like when the guy's mouth opens,do it more slowly.Another example is when the girl's arm moves from her belly do the full motion of her moving it from her belly to her mouth.In the animation it kind of jumps from her belly to her mouth,it doesn't look too smooth and realistic.It is a problem I see in both previews.
Other then that real good effort on both your previews,hope this helps you :)