Definitively slay the mythology that module-making is a mystic domain of Drupal druids.



https://api.drupal.org/api/drupal/core%21core.api.php/group/extending/


https://api.drupal.org/api/drupal/core!core.api.php/group/hooks/



Use Git: don't be afraid to change things.


Use a debugger.



### Hooks work by naming convention.

To implement a hook, take the 'hook' part off the hook name and replace it with your module's (machine) name.


### When to Contribute?

 When your module fills a need larger than your precise use case.

Note:  If you just want to build a module, finding a module idea that one or more people have been asking for is a good way to meet a need and avoid duplication.

See also http://groups.drupal.org/
contributed-module-ideas


### Finding a Drupal Function that Does What You Need


* Identify a page that produces output like what you want to see.
* Look up the page callback function for that page's menu item.
* See what functions are used (or database queries made) in the page callback function.

`grep -nHR --include=*.module 'admin/appearance' modules`


### Error messages mean progress!

`Parse error: syntax error, unexpected ';', expecting ')'`

You are having an effect on the world.  Or at least your local site.