One of my favorite ways to break the ice with people who claim that they can never draw anything resembling anything is to offer them to draw a shadow :) It is always better to start with something simple, but complex, like a palm with fingers or a flower. You will need a good source of light (be that a lamp or the sun) - which is a mood booster by itself :) And then you ask them to follow the contour of a shadow - it is a self-explanatory thing - and it does not take long. And then you have a page with a recognizable thing drawn just now! But even for people who do not need a pep-talk and for people who are good or even great at drawing, there is a lot of delight in tracing shadows, be that what you start with or add as a detail for a background.
For me, shadow is such a different way of looking at an object - it magically opens up dimensions despite actually flattening a 3D object into a 2D view. You can spend some time finding the angle that matches your current whims and follow shadows within shadows if you want more complexity with multiple sources of light. I enjoy collecting shadows when I am in a museum looking at sculptures, and sometimes (for example, on a Ruth Asawa show), objects move, so you have moving shadows to draw!
This agapanthus was fun to draw, but having that little shadow portrait made that page extra special for me - I understood some mistakes that I made after drawing the shadow too and it gave me more time with the flower - so I noticed more details and now am ready to go back and draw it again :)
