Get out a regular number two pencil and look at it. If there is not a pencil around look at another basic object such as a cup. Begin to name off observations you have about the pencil or object. If you cannot think of more than 10 characteristics about the pencil or object you can improve on being observant. Sure it is a simple exercise but it provides insight of how many small details we are truly glancing over as we go throughout our day.
Some hints for exercise: Color of pencil, color of tip, is the tip sharp or dull, length, lettering, color of lettering, eraser, eraser size, marks on it, weight, is it straight or bent, does it roll evenly on a table, etc.