Intro to 3D - Vending machine concept progression

I was set the task of designing, creating, texturing and rendering a vending machine for my Intro to 3D module at University. These are some of my initial design sketches:

I decided on the machine on the lower half of the page above. I went and did small thumbnails of details on the vending machine, a mood board giving a feel of the object and a digital drawing of the machine from the front and side views. 

I then progressed the design further by creating 4 pictures of the machine from different angles, all to scale, a colour perspective drawing and a digital board for it.

Next I am going back to make changes to the design, namely how the bottles dispense, a coin slot, a form of power and to add more textures to the perspective drawing to give it a more real look.