Research is the key to creating good civs and ships. Gather materials you need for your Civs graphics, Leader portraits, Citizen portraits, logo. backgrounds and foregrounds Come up with a theme and write back story based on the theme what your civs race is about and also add it into the description briefly telling player what's its about.
Think about how you want your leader to be. Attitude. Personality. Personal history. Military training. Diplomacy. Factor all this in when you write your flavor text. Keep brief, short and sweet. Don't frustrat yourself trying fit in every little detail. Less is more. Be creative.
As for ship design. Have you ever built a plastic model kit? The principal is the same. Only things miss are glue and instructions. Use your own imagination or find pictures of ships to inspire you and make your own custom ship based on that inspiration.
If you're going to replicate from scratch ship designs from pictures or schematics don't try to make them look exactly as they look in pictures or schematics. Add your own personal touches that make them unique and stands out from everyone else.
Very important to utilize the scaling tools in the ship designer to resize and blend the ship parts you use. The best ship designs use ship parts from more than one race.
Don't be afraid to experiment. Don't be afraid to ask questions. Most important do it for you. The only person you need to impress is yourself.