Get as much experience yourself with what you will be asking students to do. There's no substitute for learning by doing. You can even request a mentor to help walk you through steps of your assignment before the course begins.
One of the great benefits of Wikipedia assignments is the opportunity for students to collaborate with each other and the Wikipedia community. To take advantage of that, assignments should be designed to have students work in public (rather than in personal sandboxes) as much and as soon as possible.
Be sure to document the students' assigned tasks on your course page. That way, Wikipedians will know what your students are trying to do and can help them along with minimal confusion.
A series of small tasks before the assignment starts in earnest is important for helping the students learn the ropes. Here are some typical tasks and instructions:
Click the “Edit” tab (located between “Read” and “View History”) to make several edits to your userpage. Include as much or as little personal information as you’d like.
Add a Userbox to your userpage to identify yourself as part of the Public Policy Initiative. Insert the following code to the top of your userpage:
{{userboxtop}}
{{User WikiProject United States Public Policy}}
{{userboxbottom}}
If students are starting new articles, have them begin in a personal sandbox. They only need to stay in the sandbox long enough to create a stable starting point. Once an article is developed enough not to be deleted, moving it out of the sandbox as a live Wikipedia article is the best way to encourage collaboration. Getting new articles to appear on the Main Page as "Did You Know" entries (which require well-referenced starter articles with about 3-4 paragraphs of prose) is a great way to boost interest in students' articles, and offers a tangible sense of accomplishment early on. Online Ambassadors can help with that.
If students are expanding small "stub", beginning from a sandbox is also helpful. Small articles that are expanded by a factor of five within a short period (and are well-referenced) are also eligible as "Did You Know" entries, so working in a sandbox until reaching that threshold may be a good idea.
If students are revising existing large articles, have them draft their first significant edits (e.g., a new or heavily revised section) in a sandbox to get the hang of things. Subsequent edits should be done live, with negation with other editors on the article's talk page as needed. This is much more effective than fully rewriting an existing article in a sandbox and then replacing the article all at once, which may antagonize other editors.
Once students have moved their work out of sandboxes, or even before then, you can help get the attention of interested editors by leaving notes about the student projects on the discussion pages of related WikiProjects. See the WikiProject directory to find relevant projects; there may be multiple WikiProjects that are relevant to each article.
Once articles are well-developed, students can request a peer review. These do not always happen in a timely manner, however, and should not be mandatory parts of the assignment.
