Design
One thing we could all use is a lesson in Design. It's great to study how to do the technical parts of hard modeling but without design senses, that process is very hard.
This page will have videos that help with thinking about design. If you know of a good design related video, email me or leave a comment below.
Inspiration
This is what a master of design can do. Turn everyday objects into Sci Fi Objects. Notice the design language through out his Designs, Bevels, Grids, Details. Notice the simple areas and the areas with high detail.
Here are some more. Just incredible. Kit-bashing in 2d basically, but his kit bash objects are in his head. He probablly has reference images he pulls from.
Beginner
Creative Shrimp have an excellent Website with a page on shapes and why to use complex and the opposite, simple shapes in your designs.
Here The blender Bros talk about several rules he follows when he designs hard surface objects. Some of then echo Creative Shrimps ideas. My favorite is the 70/30 rule in which it's 70% Minimal detail and 30% high detail. I really like his videos and always learn something useful in terms of Design.
Intermediate
Brother Baston.,He draws some spaceships and describes what drives his designs. For instance his ships have nuke engines and draws what he thinks they should look like. And scales for ship skin. So His idea for designing is to have a paragraph of what the ship does, how it's powered, what type of ship. He then draws the basic shapes and then adds the appropriate details. LIke a battle ship would have Turrets and huge weapons. He talks about shape language and the importance of this in his designs.
If you can draw then Brother Baston has a great little tutorial on how to make a spaceship. He describes his ideas of why he chooses to draw the parts. A crew quarters for one ship, an ai powered ship, each one would be different. A bridge for a human crewed Ship etc.
Advanced
Star wars style. He has some valid points. But also I think the context is important. What planet is the ship from, From a rich planet or a poor planet, who's using it a smuggler like han solo, or a world government like the empire. (who has tons of money to build more advanced fighters.) He talks a little about design choices that might be considered to help fit a theme or design language. (Which is made up of all the starwars movies, tv shows, etc.) You wouldn't introduce startrek designs into starwars right?
But you need new designs. What I think is it's ok for lucas films to go in a different style that's new and fresh also, if they didn't you wouldn't of gotten the naboo fighters, or the droid army. But if you haven't seen the Bobo Fett tv series, the droid battle droids at the end followed with the design language of the droids in the clone wars. But different enough to say wow those are cool. I seem to remember an anime where they introduced a design of some Ship that was totally different than what was seen in the show and it had many cool features the old ships didn't. This departure can be used as a plot device so it isn't necessarily bad.