Thank you for your application!
Something that I find we don't exactly tell many applicants, is that applying for artist is something that is ongoing. What I mean by this is that when you post your app up on the forums, and you are not accepted immediately (which, btw, never happens unless it's an old artist returning) then never fear, this is just how applying for artist works. We need to figure out if you're a good pick for artist, and that is something that we cannot, unfortunately, do very fast.
To improve your chances, make more builds practicing either in themed builds or on your own worlds using our resource pack (make sure to add them to your app here in the form of a reply!) and spend time on the server so that people get to know you and so that we staff can tell if you are mature enough for this rank. During your time spent on the server, make sure to participate in jobs as well.
As for your pics, the first two on the app do not show much of building but mostly terrain, which is good to see on a themed build, don't get me wrong, but is of secondary importance to structural work.
The third pic shows that you are pretty competent using the default pack, but we highly recommend you use our own resource packs in the builds you post here, as well as imitating some of our styles on the main server. If you want to use our packs on your own worlds, you can find the downloads here:
Resources | Minecraft Middle Earth
Thanks again for your application, we can always use extra builders, and if you have any questions/need help/or just want advice, you can always shoot me a pm!
bender