In the photo of a quilted flower at the top, (which is artwork from the cover of Susan Brubaker Knapp's DVD workshop "Master Machine Quilting", available here) I was startled when I first realized that she used both pure white and black threads in this "yellow" flower. Once you see it, it's obvious, and really helps add depth to the artwork. I can't use my own artwork to illustrate this, I haven't mastered it yet :-)
The great thing about learning to observe is that you can practice it anytime, anywhere. If you are ever just waiting somewhere, look around and see how many things you can notice about the world immediately around you. Look at both the big picture and tiny details. Look for shapes and colors. If you have kids, train them early to pay attention! It's a valuable skill in other areas of life too. Think how nice it is when someone else remembers something going on in your life and thinks to ask about it, or remembers your name! It's all the same thing, observing and paying attention. It even helps you remember things if you make a point to notice it, like someone's name. It's a good brain exercise for anyone, not just artists.
Here is a quote from the book I'm reading (see yesterday's post):
"You think that when your eyes are open you're seeing, but your brain deceives you, reporting stereotypes instead of the image your eyes actually see. Your logical brain gives you a quick and easy symbol-the tree looks like a lollipop, the eye looks like an almond-so it won't have to work so hard searching for individual differences. You must trick your brain to see what is really there."
Again, when it comes to artwork, you don't have to recreate what is there, but it's extremely helpful to recognize it.
So, you can start right now, look around wherever you are and see what you can notice, and have fun!