Generally quite good, particularly on the shading. The line work looks just a little choppy... are you using layers with your drawing software? If you sketch the general shape on a lower layer, then draw on top of it, you can make your lines much smoother by 'sculpting' precisely the right portions out of the sketchy, less proportional lower layer. You do have to play it by eye though, and as much as possible I'd recommend comparing your anatomy with other artists to make sure you've got the right mix of style and substance. Another thing you can practice with is using less free-hand tools to make straighter lines. It looks like that trident came out more curvy than you might've anticipated. With a traditional art, you can use a ruler to make sure straight edges are consistent. With digital art, there's straight line tools to get this to work.

Things are looking good though~ Keep it up! Practice makes perfect.