Rojero, I had the same problem with the Verdurans (I almost quit several times) and the only thing that kept me going was random experimentation. I used vegetables as my inspiration, but I ran out of ideas after the destroyer. So, I just started adding shapes (especially spheres and cylinders) to my basic hull and by accident created something I liked. They didn't really turn out the way I expected, but in the end I do like them.
PS. Don't feel obliged to make them look feline (unless you really want to). Human ships don't look remotely human, and I don't imagine aliens would make self-portrait style ships either.
PPS. Try not to feel discouraged about all the great ship sets out there - most of their creators have many years of experience. It's impossible to be perfect the first time (and you can always make a newer Version later).
