This is a pretty simple hint, but if you’re like me, and have a number of templates that you’ve created in Pages, you probably wish they were organized in the Template Chooser, rather than being all displayed together in the My Templates section.
You can create your own sub-grouping under My Templates by navigating to your user’s Library » Application Support » iWork » Pages » Templates folder. Here you will see one folder (My Templates) which contains any templates that you’ve already created. You can create new folders at this level, adjacent to My Templates for your new subgroups. Note that you can’t create folders inside of My Templates; they won’t show up in Pages.
In my case, I created folders for each of the companies I work with, and one Personal folder for my own letters. In each folder, I have Letter.template, Invoice.template, Case Study.template, etc. My Personal folder only contains Letter.template.
After creating the folders, simply move your templates from My Templates into the appropriate new folders. You can/should leave the My Templates folder there, even if it is empty. If you delete it, Pages will re-create it anyway — it’s required because it’s the default location for any new templates you create.
If you want to again see all of your templates in the Template Chooser, just select My Templates from the left-side hierarchy. (Any templates left loose in the Templates folder, however, will not be shown, even when selecting My Templates from the Template Chooser.)
Annoyingly, the My Templates folder is always re-created each time you go to save a new template. Once created, this will then show up as another sub-group My Templates in the Template Chooser.
If you’d like to undo this hint, simply move all your templates back to the folder My Templates inside Templates, then delete all of your now-empty subgroup folders. Next time you open Template Chooser, all of your templates will simply appear under My Templates, and there will no longer be any subgroups (including the annoying My Templates subgroup).