As you launch yourself into (or continue) what will hopefully be many productive years as a Drupal programmer, I hope that you will continue to keep the principles of Chapter 2 in mind and avoid the mistakes listed in Chapter 3. You should be able to keep returning to Chapter 4 and outside references such as the Examples for Developers project (http://drupal.org/project/examples) for examples and ideas. And for further study, there are suggestions sprinkled throughout this book and in Where to Find More Information.
In closing, I’d like to offer a few final programming tips and suggest a few development tools that you should find useful in your endeavors.
The Drupal community has developed several very useful development tools that can help you avoid making programming mistakes, adhere to the Drupal coding standards, and debug your Drupal sites and Drupal code. Here is a list of the most useful development tools: