Cut it in half
Tier your decks (space them 3 to 4 bocks apart with the bridge being a bit taller, 5 to 6 bocks tall.
Plan out your main area locations such as Bridge, Hanger, Engine Room, Computer Core, Weapons, Life Pods, Hatches, RCS thrusters, Impulse Engines bays, sick bay, lounges, etc. 
Map out a good - basic - turbo lift path that connects all the decks and spans fore to aft, port to starbard covering limited space but routed to key locations smartly.
Map out your decks starting with the outer corridor for the largest deck. Then the smallest deck inner most corridor. Drop that down and work outward as you go. Each deck adding a new corridor if applicable. Keeping all the corridors (where possible) aligned with the ones above and below them.
Route a basic J/T system (Jefferies Tube)
Modify the Turbo lifts and corridors as needed to make sense.
Pattern out rooms.  Look at the latest work on the E for crew quarter ideas. 

Watch a few of the videos on the E build and other ships to get an idea of how we built the ships. It will come in very handy as a guide.

Good luck

Looks cool, good luck with it.

Looks incredible so far!  Keep it up!