Hi, donttakemyguz. Welcome to the forums.
It's hard to give advice to someone you don't know, but sounds like a very ambitious idea. So the best advice anyone could give is, take your time and enjoy it.
The collectors cruiser looks great. The only thing that I can see wrong with it, and it's minor, is the shadows. It's up to you if you want shadows across parts of the ship, it looks nice standing still, but when the ship turns it can look wrong.
Make good use of copy and paste. You can move parts of ships around and generally make them look different.
Make good use of layers. Take part of a ship and change its colour, rescale, rotate, flip it.
These things can go a long way to creating a full fleet of ships.
Hope some of this was helpful.