Hi! I am pretty bad when it comes to building, so I thought I might improve on that. I have created a kind of futuristic, spaceship hallway, and wanted to know what you guys thought of it! Constructive feedback is greatly accepted.
You can see the game here: showcase - Roblox
Definitely managed to make it feel futuristic, I really like how it looks. I don’t think you are near to being “pretty bad” at building. Good job and great work! 
I definitely love how you made it look futuristic with moody blue colours, it does undoubtedly give me that feel of a Sci-Fi ship model that I would possibly see within a movie.
But, for player wise in game, I recommend making the height taller as it does look a little crowded and not exposed enough. Also, if you removed some of the details it would also make it appear to be more open and not like the walls are shutting on you.
Hopefully my thoughts on your build help enhance your style, but do not feel the need to adjust to my expectations as it just simply my personal like of design and experience. Good luck in the future, keep practicing and you will eventually get there.
I like it, however; unlike @xStarfully opinion I would not suggest removing detail and making the build larger because having a almost claustrophobic feel adds a lot to a space build in my opinion. It might look good if you had a space skybox with a few small glass windows looking out into space ( maybe even having those windows on the floor or roof.
Okay, so, the white parts(neons, lights…?) Looks like they are out of place, like they don’t belong there, and someone glued them there.
The wall panels, randomize them, make some of them different.
Change the ceilings, it looks same as floor, maybe add light in ceilings, or some wires, or pipes or I don’t know, something.
On the end of the hallway, if that’s a door, make doorframe, and make sure that parts are aligned nicely.
Don’t be afraid to use increments, for moving use values that are like 0.2, 0.4, 0.6, 0.8, and 1.
Try avoiding patterns that repeats, I made that mistake alot.
Here is my example of sci-fi hallway:
What I did here to avoid repeatnes, is change one window into the light, added some handles around the window, added a vent in floor…but u still can see pattern there.
Good luck with your building, that’s looking great, I love colors and your imagination.
looks awesome maybe put some sci fi pipes in the corners on the roof for electrical realism other than that all I can say is awesome job 
I’d really like to walk through this hallway with a laser gun
Great work!
I like the style but I think that you might have missed this. sorry or being a perfectionist person 
