I dig it. I think it looks awesome. I really like the ring shape around the sides. It’s very unusual, but very appealing.
Just right off the bat, you could use some windows, doors, antennae, things of the like. Think about what the ship is used for. Is it a cargo ship? Add some cargo bays. Is it a fighter? Guns. Is it a carrier? Fighter bays.
Also, I think you should spruce up the nose a bit. It’s easy to tell the back end by that incredible set of thrusters you have there. By comparison, the front end is a series of repeating forms, extruded and scaled over and over. I’d say some kind of prominent control room would be an order. Something that protrudes beyond the front of the ship.
Nice job! Sorry if I’ve come on like gang-busters. You are in the focused critique after all! You’re definitely onto something here, I can’t wait to see what it is.