Mix arugula with fresh basil and mint leaves. If the leaves of the herbs are on the larger side, feel free to give them a rough chop before adding to the arugula.
Line the outside edges of a rectangular dish or platter with the arugula and herb mixture.
Arrange the watermelon and feta cubes in alternating stripes, beginning and ending with watermelon. The first two stripes will be about ⅓ shorter than the last 3 stripes, leaving room for a square shape of blueberries.
Nestle the blueberries in the square that remains in the top left corner of the platter.
When ready to serve, drizzle the top of the entire platter with fresh mint vinaigrette.
Note: the salad can be assembled and kept covered in the refrigerator up to 4 hours before serving. Do not dress the salad with vinaigrette until ready to serve.