I agree on the head size and trunk shape issues. The thing about the trunk is that right now it feels like several straight pieces stuck together rather than a smooth, continuous shape if you know what I mean. But for me, the biggest issue in the image is that the background and subject have the exact same color palette, saturation level, and value range, which makes the image feel repetitive and same-y and reduces the impact of your focal point. Right now the elephant just blends into the atmosphere rather than standing out.
Also, you might want to be careful with how much you reference photographs that are not yours and are not stock. Stretch your artistic muscles and alter the pose to make it your own and enhance the image. Why is the tail up, is it helping the image? What if the trunk was up instead? What if the elephant was rearing or running, would that make the image more exciting? Determine your goal with the image, the message you're trying to get across, then research your subject and explore how to portray it in a way that meets your goal.