If you can't find the categories on your wiki, check their name on your wiki at MediaWiki:Commonsmetadata-trackingcategory-no-description, MediaWiki:Commonsmetadata-trackingcategory-no-author and MediaWiki:Commonsmetadata-trackingcategory-no-source.
Try to find groups of files whose description pages are similar, so that we can use bots to automatically take that information and put it into an information template.
Once you find groups of files with information in the same order or format, you can use a bot to add the information template around the existing information (example). If you don't have a bot, you can ask a bot owner on your wiki to help you.
It's better to have an incomplete template than no template at all.
Alternatively, you can use the Labs tool to see files that don't have any of the accepted information templates. The tool tries to guess how to add the information template and suggests a possible edit for you (example).
Sadly, this tool is limited to English wikis.
Add machine-readable markers to information templates
For wikis outside Commons, we need to check the list of interwiki links to see if your wiki already has an Information template.
Your wiki doesn't have an information template yet[edit]
Add it to the list of interwikis so other people on your wiki can find it.
Add the template to the files on your wiki; the Labs tool can help you as well.
Your wiki already has an information template[edit]
If the template on your wiki was imported from Commons in the last few years, it probably has the markers. Otherwise, you can add them:
Add the markers as HTML IDs in the <td> element preceding the <td> element that contains the actual information. This means that the <td> element you mark is the one containing the title of the field, not the field itself. Example:
Add machine-readable markers to copyright templates
In order for tools to be able to correctly identify the license of a file, we need to edit the license templates to add machine-readable markers. This is easy and only needs to be done once on each licence template.
Add the licensetpl CSS class to the table or div wrapping your template.
Add the licensetpl_short class to the element containing the short name of the license, like "CC-BY-SA-3.0".
Add the licensetpl_long class to the element containing the long name of the license, like "Creative Commons Attribution-Share Alike 3.0".
Add the licensetpl_link class to the element containing the link to the license deed. "http" must be inside a nowiki tag: "<nowiki>http://</nowiki>creativecommons.org/licenses/by-sa/3.0/". This is because the value must be the plain string, not a hyperlink object.
Optional tags:
Add the licensetpl_attr_req class to an optional element containing the text true or false whether attribution is required by this license.
Add the licensetpl_attr class to an optional element containing the attribution requested by the copyright holder, like "Jane Doe".
Add the licensetpl_link_req class to an optional element containing the text true or false whether a link to the license is required by this license.
If a template contains several licenses (for example, successive Creative Commons versions), add the markers for each license, and wrap everything in a block using the licensetpl_wrapper class.
Assessments that are not licenses (Public domain, fair use)[edit]
For Public domain assessments, fair use assessments etc., use the same CSS classes:
licensetpl for the table or div wrapping your template;
licensetpl_short for the short name, like "PD" or "Fair use";
licensetpl_long for the long name, like "Public Domain" or "Fair use of copyrighted material";
licensetpl_link for a link to the file page itself.
For non-free images (under fair use, etc.), also add the licensetpl_nonfree class to an element containing the text true.
See an example: Fair use template on the English Wikipedia.
Note: Adding the markers to the page doesn't mean you have to show them. For example, you can hide the field containing licensetpl_link for a Public domain or Fair use template using CSS, as done in the example linked above.
Measure your progress
Once you've added the markers to the templates, you need to wait a little for the markers to propagate to the files. After a few days, you should see a change on the progress dashboard for your wiki.