A list of things to be done. To add something to be done, add another bullet point to the list. To claim something, add a comment after an item on the list. Once an item has been done, it can be archived.
Expand help pages and general documentation. Lack of introductory or explanatory information is a barrier to new volunteers. Some aspects of Wikisource are assumed by experienced users but not documented anywhere for a new user to find.
Create a standard policy for serialised fiction and articles.