I like to create a "workspace" folder that contains all the files related to the addon. This includes all files used in developing the addon as well as those used in the release.
Create the "workspace" folder somewhere convenient, such as on the Desktop or in your Documents folder. Name the workspace folder with the name of the addon. For example: Rochelle Replacement - Jill Valentine Casual Outfit
The following sub-sections explain the sub-folders and what to include in them.