I've added a new page type to the SMW Community Wiki, at smw.referata.com, for "tips". These are hints and techniques, supplied by users, for how to accomplish specific tasks using SMW or any of its related extensions. There is a lot of accumulated wisdom out there about using the SMW system, for a wide variety of purposes, so this will hopefully provide a people for people to record some of that valuable wisdom for others' benefit.
I should note that, ideally, this set of pages would go on semantic-mediawiki.org instead, though that site's closed registration makes that impossible: if that ever changes, it should be easy to move them all over there. For now, the current place should be fine, I think.
Here's the form for adding new tips, which is also linked from the sidebar:
And here's the page that lists the tips, filterable by extension; it currently features just my inaugural tip: