Apple provides several different project templates with Xcode so that we may easily set up new projects. However, these project templates are rather generic. In fact, I quickly found that as soon as I created a new project, I would immediately modify in a very consistent manner.
Since one of the purposes of computers is to automate repetitive tasks, I decided to design my own project template.
The first thing we need to do is locate the built in Project Templates. They are located at "Macintosh HD/Library/Application Support/Apple/Developer Tools/Project Templates/"
Inside of this folder are several folders that bear highly recognizable names. Yes, these folders are the group names that appear in the New Project Assistant. Inside of these folders are the actual project templates.
Making the actual custom project template is rather straightforward:
1) Make a copy of the desired project template.
2) Double click ProjectType.pbproj. Xcode will ask you if you want to upgrade a copy, click yes. A new .xcodeproj file will be created.
3) Modify the project to your desire. However, do not modify any that has placeholder brackets. Ex: "<<PROJECTNAME>>". The place holders will be modified when you create an actual project.
4) Close the project.
5) Trash the old .pbproj file.
6) Trash the build folder.
7) Change ProjectType.xcodeproj to ProjectType.pbproj.
8) Control click on ProjectType.pbproj and select "Show Package Contents". Trash the username.mode1 and username.pbxuser files.
9) Change the name of template folder to the name you wish to appear in the New Project Assistant .
10) Place the new project template in the appropriate folder. For example, if MyNewCabonProject/ was placed in "Macintosh HD/Library/Application Support/Apple/Developer Tools/Project Templates/Applications/" we would see a project of type "MyNewCabonProject" in the "Applications" group in the new project assistant.
If you desire, you may create a new folder in "Macintosh HD/Library/Application Support/Apple/Developer Tools/Project Templates/". Doing so will create a new grouping in the new project assistant. The assistant sorts everything by alphabetical order.
As an alternative, you can place new project templates in your home library: "~/Library/Application Support/Apple/Developer Tools/Project Templates". Note that only you can see your own templates if you do so.
Also, see Xcode Hints for related information.