The piece itself is good, the color and the layout of the image is very visually appealing. The contrast between the soft fruit and the classic summer sunny wood table is delectably enhanced with the heart cut out in the center of the image.
While the colors and texture is fantastic I feel the image is very center heavy. Your eye is brought to the center of the heart in the mellon and it can travel upwards with the similarity in light on the upper half of the mellon. Though it doesn't travel elsewhere commonly. I wish the white and the light was pushed a bit more though the top of the mellon. Though with the fact I assume you took this image outside the time of day affected your piece.
For a couple of different visual interests try a similar piece in different times in the day.
I love how deep the colors came out, its not too bright or really deep, there is a balance that is very nice here.
I also must congratulate you on finding a Watermelon that was nice enough to do this to. Cutting that heart into the fruit must have been a task as the lines are actually curved and not "Digital Analog" looking with straight lines across the top, much patience must have been had in-order to do this.
The orientation of the picture is good too, choosing to cut the ends out and focus on the heart, rather then showing the entire watermelon slice.