David is one of my favorite writers/photographers. His book "Within The Frame" has helped me understand the WHY of photography. I can't recommend it enough. He now has come out with a series of e books.“Ten Ways to Improve Your Craft. None of Them Involve Buying Gear.” is the first. The second, "Ten More" builds on the first. I believe there will be one more. The price is $5.00 each. A great value for so much photographic incite and information. He even gives an exercise to go along with each chapter. Find them here.