Drupal 7.x Development - Naming conventions
I'm a bit surprised that you haven't found anything on the internet that could answer your questions. Here is an article about coding standards for Drupal.

Anyway, here are several things I always do with naming, functions and directories (that doesn't mean it's the best conventions):


The only directory you should work in is ./sites (please never ever edit something in the other directories).
The contribute modules you download should be placed in ./sites/all/modules/contrib
The custom modules that you develop yourself should be placed in ./sites/all/modules/custom
When you create a custom module, chose a simple and suitable name of it, preceded by the name of your project (better), for example myproject_blog.
The .module and .info files should have the same name as your module's, for example myproject_blog.module and myproject_blog.info. It will automatically make the relationship between them.
All the functions that appear in your .module file should be named by your module's name, for example myproject_blog_revision_publish().
If your custom module needs a table in your database, the name of your module has to show up somewhere, for example $schema['myproject_blog']. If you need more than one table, keep the prefix and add some explicit suffix.
Idem for the custom themes in ./sites/all/themes.


If I forgot something, just ask ;)