I believe everyone is creative and can draw. Yes, there are various levels of technical excellence when it comes to rendering, but whether you think you are good enough to draw, should never stop you from drawing.
I practice a lot of techniques to help cultivate my drawing skills. One technique I would like to share is from Dr. Betty Edwards book, Drawing on the right side of the brain. The method is the upside-down drawing exercise.
Dr. Betty Edwards has spent her life's work understanding how to best teach drawing and shares many methods in her book that aim to access the right side or visual side of the brain. The upside-down method is simply drawing from a reference photo, but drawing from the photo turned upside down.
An upside-down person, for example, becomes difficult to recognize. When drawing something unfamiliar, the brain is forced to work with shapes and lights and darks instead of focusing on the familiar features. Look at Figure 1 to see how differently the brain perceives the same photo shown in A. compared to B.