This little attempt is a significant step. Making a new part, even a simple one, is a very important step. I have also noticed that in the last couple of works, there seems to be more of an attempt to get rid of any signs of copy and pasting, which I consider to be essential. And I also appreciate how you are also adding smaller registry markings the the nacelles ends.
One of the next steps that I would focus on is the shade of the color you use for your parts and registries, so that they are too light or, specifically in your case, too dark or bold. I like how the registry for the Valhalla isn't too dark for example.
I would also try to notice the details of the parts that you use. What I do as I look at other people's works is play around with the details in my head, and try to come up with variations. I draw details and curves that draw my eye in the air, and try to think of new details for future designs. They are usually similar, but not identical. Depending on how good you are at drawing, you might even want to try to brainstorm ideas by sketching. The harder part might be figuring out how to apply your ideas in-program within a reasonable amount of time, so I would pace yourself, and try to improve your attention to detail little by little, for either every ship you do, or every batch.