Here are my two cents - - trying to make a novel shape out of nothing takes a lot of work. But once you have the shape down, it'll get easier and easier.
With that said, given your skill level, I suggest that you bypass the shape creation step and modify a pre-existing ship. Go to the Wiki and find a low-poly model and play around with it. Play around with tools such as bevel, inset, and smooth. Turn it into a high-poly ship. This might step on people's toes as it deals with authorship, but you can do this purely for your own experience. Of course, if you end up with something nice, then share it!
R