It's kinda hard to give any specific advise as how to improve the model 'cause the design is fine. But as always, detail is what would make it believable. I know you wont change this, but I think the all-crome design is outdated and cheesy. Sorry. I like it alot though, don't mistake that.

windows... You really should make them transparent, and just build something simple inside. Even a flat cutout of some shapes would work. Cheers, Pingo.

I agree with Denb, your design is excellent and details will pull off what you have done so far. And while the all-chrome thing may be cheesy I like it's effect here. To me this has kind of an updated Flash Gordon feel to the imagery, very cool. Great mechanics on the docking design.

if you can, dirty it up, thats what I think makes a building look real, otherwise great job

I think you have too many shiny/reflective surfaces, try swapping some out for a more matt look. And i agree give it some dirt and wear and tear. Make it tell a story, scorch marks from spacecraft, show a wind direction when adding damp/rust/dirt. Maybe one tower is a little damaged and under repair. Wonderful design, can't wait to see it's progression.

thanks for the tips :), yeh i think im allergic to decent texturing, or im just too lazy to learn to do them properly, i will try with the dirt, rust and matt textures

hell, i can't give you any advice...but this image is looking fantastic. you created it with C4D -ONLY- ???? hhmmm...be back soon - have to look if i got some money to spend left in my pocket... :) really, i hadn't known that the C4D-renderer is able to render such powerfull images and effects?!? amazing.