I absolutely love this series of Urban Sketching Handbook by Quarry Books. They are just beautiful and are designed to look like sketchbooks including the elastic closure. They are straight to the point with many illustrations of the principles, tips and techniques discussed. This book focuses on composition, scale, depth, contrast, line and creativity in sketches of the built environment. The author emphasizes how delightful it is to take the time to stop and appreciate the diversity we can see in building in different places and how they reflect culture and how people use space. Building and cityscapes do not need to be spectacular to be a good subject for urban sketching, but our creativity in handling the subject can make every sketch a thing of beauty and wonder.
The last third of the book shows what effects can be achieved by using pencil, pen, watercolour or mixed media. In fact, many types of writing and drawing implements can be used for sketching! How much stuff you bring along on a sketching exhibition will be limited by the weight of your bag!
Campanario, Gabriel. The Urban Sketching Handbook: Architecture and Cityscapes: Tips and Techniques for Drawing on Location. Quarry Books, Beverly, MA, 2014.