In that case you should understand more about reflections. Chapter 2 describes the nature of reflections and elaborates on Chapter 1. Underlying principles are discussed and 3D imagery is used as reference. Before you read Chapter 2, read Chapter 1 first. Chapter 1 just might be all you need.
Transparency is more difficult to fake.
Chapter 3 discusses this troublesome material-property. Because transparency often deals with reflection, it's also taken into account here. Here are the 3 chapters, each one with increasing depth. At all times I will tie the information to its usefulness in drawing. If you have any comments, suggestions or questions, don't hesitate to contact me.