Fischi's Spaceship for the Monthly Art Challange

Evil_Fischi

Hi there,

I'm working on the Monthly Art Challange of March on the Spaceship concepted by Long Pham.
I hope you can give me some nice tips and tricks for modeling a spaceship, because I haven't modeled a vehicle yet.
Here is the Referencepicture:

Evil_Fischi

Here are the first blockouts. I am struggeling with the backpart (the blue one). I am not shure how I should design it.
Any Ideas?