Worst thing you could do is give up, you'll learn much more by sticking with it. Be persistent, pay attention to detail, and just keep plugging away. You'd be amazed how a few spot on details can change the whole look of a bridge. I'll give you some examples on your bridge, if I may:
the colors of the walls and floor seem way too saturated - check your refs again and try to match that as closely as possible. When you're drawing lcars panels, try not to simplify - again, check your ref pics; if, for example, there's a line with a slight gradient and it gets thinner on a segment, don't just make it straight and flat orange - details are everything.
Finally, you can greatly improve the quality of your renders with a good lighting setup. For starters, even just the skylight would do to get the ambient occlusion, that alone will greatly enhance the look of you renders.
And if you need help or advice, feel free to contact me, I'll do my best to help you with what I know.