Using Smart Guides set to 30 degree angles. (located in Illustrator – Preferences-Smart Guides) Turn on Construction Guides
Make sure under View menu that Smart Guides are checked.
Isometric view is one way to get a rudimentary view of objects in 3 dimensions. Build some blocks in 3D and color them appropriately with one light source. Pick one color, then use COLOR PANEL to Adjust the K (black).
Construct 3 different sized blocks and color them appropriately with one light source.