First, kudos to you in capturing this bird (or any bird for that matter) with full wing extension and with no motion blur. It is not easy for they move at roughly a rate of 25 feet per second - I have tried for the better part of a year on and off to get a good shot of a hawk in flight to no avail. Now onto the critique. As I mentioned you got a great capture of this bird in flight but to truly make it stand-out and have wow factor it has to showcase the details of this seagull. The underside of the bird is too dark for the viewer to fully appreciate all the details in the color shades on the bird not to mention the full complex textures of the wings/feathers. Lighting and luck are the key ingredients into turning this into a wow shot instead of an average shot. An underbelly shot generally won't do it for the underside is in shadow. A side profile shot or top view would be best for the natural lighting is illuminating all the lovely details for you. Looking at the original you were emulating it shows the viewer with sharp clarity all the details of the wings from the three rows of feathers to the various colors in the wings to the details of the head. Now the luck. Well that comes from being there at the right time to capture the moment. It will take a lot of luck and patience, but in the end it will pay off.