Hi Roemer - welcome and I hope you'll enjoy yourself here.
I agree with Zab - the whites and metal areas could do with some more contrasts to balance them with the good job you did on the green. Overall a very neat paint job with good brush control - in other words, great foundations to build on.
You may want to consider setting up a WIP thread - I'm also relatively new to the site and the hobby and I've found that it's a great way to meet people and learn.