Image isn't showing (you need to use the url that has 'http://i.imgur.com' in it, not the 'http://imgur.com/a/' one. If you can't find that one among the sharing options, or can't find the sharing options at all, and you're at the /a/ one, right-clicking the image and selecting 'copy image location' works too).



Not a bad start.

One thing I notice is that the section of the wings between the 'body' and the engines doesn't quite match the angle or width of the external-most wingsections.

You're also using more colours than necessary: the image has 64 of them while you would be able to reach the same effect you currently have with maybe 9-12 of them. (3-4 blues, cyans and greys each should be quite sufficient for this until/unless you get to further shading. Even so, I'd increase the contrast between them some, and it's probably also possible to have one of the light cyans/light greys be the same shade and use it for both.)

As for further shading, there's a few things to keep in mind. Light (including direction, brightness and colour), shape (which determines where light does or does not hit and thus where there are shadows--combined with direction of light, at least) and material (does it absorb most light? Does it strongly reflect? Does light pass through it?) Before going too deep into further shading, though, it'd be a good idea to reduce the colours you already have, else you likely end up with an unmanageable number of them.