Just for the fun : use the SsPlit function for speed modeling! :) (P = Ssplit)
The first time click an edge - Mirror enabled
Move & Create 2 lines on the volume
Click an edge
Right Click for recall the Ssplit function
Move & Create 2 lines on the volume
Click an edge
etc...
then extrude Positive or Negative faces
and as always it's difficult to select "tiny faces" - Select a Big face then Little face(s)
then re-click the Big face for deselect it! ;)
and extrude them
etc...

|