I teach a beginner's drawing class for adults and it's the most important art class of anyone's art career. My students get frustrated because what they've put on paper according to my instruction doesn't look like what they think it should look like. And therein lies the problem.
Children don't let realism get in the way of making art. They draw something based on their few sensory experiences with the object and have to rely on their hand and eyes to recreate the image on paper. They don't get hung up on what the object is that their drawing.
Adults who are beginning to draw fear the object. "OMG! I have to draw that?!". No, I say. You don't. You have to use lines and shapes to represent that. The end result is an illusion of the object. Artists are masters of illusion.
Beginning a drawing or painting or sculpture or music composition that is complex is like having one end goal and setting smaller goals to get there.
Try this (for visual artists):
Print off a picture you want to draw. Set up your paper and pencils and draw the contour (outline) of the image without looking at your paper. This will help you examine the object closely and get your brain and hand to connect. Do this as many times as you like.
Then, draw the picture in 1 minute. Time yourself so you don't cheat. No erasing! This forces you the break down that image into it's simplest form so you can gauge correct proportions and composition. Do this as many times as you like.
Practice these two exercises with different images for atleast a month as often as possible. After that month, go back to your very first image and draw it again in one minute and compare your first one minute drawing to you're last one minute drawing. You should see noticeable differences.
From here on, you'll be able to build up your drawing with textures and values etc to get the illusion you're looking for. Those are the next stepping stones which are also very important in drawing and painting, but getting over the fear of the object first is the most important aspect to beginning to draw. Even my 75 yr old student says to me "wow, I'm going home and beginning to see things way differently now! It's unreal". Exactly. Unreal. Take away the reality and your left with imagination.