The focus is a little off. Look at the boy's hand. Do a little sharpening. Also there is little contrast.
Even if the scenery and composition are good, it is often not enough to get your photo selected. Photographs that are selected tend to be those that have clear intentions for color tone and exposure. For this photo, I think careful development and processing of the tones of the clouds and shaded areas will make it easy to be selected. The use of image processing software such as Photoshop or Lightroom is recommended.
Both images need to have the shadows lifted and the blown out areas in the sky corrected.