Good capture of Lugia. The shading is very crisp and the lines are very clear. The only thing that seems out of place is the background. The clouds need more definition, it's fine to be wispy on the edges, but these almost look like smoke. The sun also needs to be brighter, because right now it's completely out of focus.
This is great! I love the background and the pose is very dynamic! All I'd suggest is to darken the shading on Lugia's body, and to, as =Heyriel mentioned, lighten the blue of the sky. But overall, I like this very much! Keep up the good work!