Not bad, not bad at all.
As for the exterior - try adding some piping, antennas, make some gaps/indentations (slabs are great for those...) Also, you can make a heat dissipator using motherboards (red/orange are best) and highlight them with lights or charged cirquits.
Also, it is good to make an indented thruster instead of a flat one. Just surround it with one or two layers of hull