Step 4. Finishing with Guidelines.
The final very important touch is the guides that layout the size and orientation of the rocket giving the blueprint that designed architectural feel. Using the line tool create a horizontal and vertical axis through the centre of the rocket’s body and window. Select both lines and check the relevant box in the stroke panel to make these lines dashed.

The second set of guides outline the size of the rocket, two lines to measure the width of the nose cone and rocket body. Again stroke these lines white and this time add arrowheads to each end of the lines. Finally add some vertical measurement lines and you are done.

I hope you have found this tutorial helpful.