Consistency with using quotations around quotes- The first card uses quotes whereas the other two do not.
Consider using a colored background for each postcard and then changing the color of the text accordingly. The white looks somewhat plain, and color could give each card more character that differentiate each one from each other.
For the Shifu postcard, the shadow goes off the page whereas the other images are all contained within the frame without interacting with the edges.
Also maybe reconsider the crop for the Shifu mobile image. Maybe show some more of his ear?
Concept is clear and aesthetic for the set is consistent.
Katie's Postcards