One of the things we need volunteers to do is the adding of TemplateData to templates (particularly high-profile ones, such as infoboxes) so that they are easy to edit.
The
TemplateData help page
explains how to add TemplateData information to a template.
You can probably think of some pretty important templates on your wiki very easily; experienced users know pretty well which templates are a big deal, and will inevitably find out when they try to use them and discover there isn't any TemplateData.
You can find an automatically-generated list of most used templates on your wiki on the
Special:MostUsedTemplates
special page.