Analyze the forms.
Compare them.
Answer questions:
Which one is bigger, closer, more complex?
Find the "end points" - the highest / lowest / most right / most left.
Lay them out on a pice of paper.
Roughly outline each piece.
Constrain proportions.
Break large shapes into smaller parts.
Compare and reference the proportions.
Continue breaking the shapes into smaller details.
.
Shade all shaded parts. Define the light side and the dark side.
No need for details at this point.
Add drop shadows.
Remember how they work - darker next to the object, then fading.
No outlines! Work with edges!!!
Now that you have all important pieces in place - you can start on individual pieces.
Use small strokes.
Take your time.