I recently picked up this book from Thomas C. Wang called Pencil Sketching, in a used book store. It's a simple book that shows various techniques to draw with pencils. Since I have tons of pencils that I'd like to put to good use, I decided to buy it and read the entire book during my train ride back home. It was a quick read, showing techniques to draw various items and what tools to use when. The author is a landscape architect so the drawings focus around things like trees, water, buildings, cars and people.
The best way to evaluate the book is to start drawing using the suggested techniques. So even thought I only had markers with me at the time, I decided to reproduce a couple sketches using markers instead. It turned out pretty good as you can see below and will definitely help with my urban sketches.