For lack of any other content, I'm going to document dumb mistakes I make while coding tags. Anyone else is welcome to replace this section. (--JayLevitt?)

* Where do you put the tag definitions?

* Container tags are responsible for their own rendering. If you want the stuff inside your container to get rendered, you'd better output it from the container. Conversely, if you want nothing in your container to render--consider it done.

* Remember that <r:tag1:tag2/> is shorthand for <r:tag1><r:tag2/></r:tag1>. If you're inside a container, you're already looking at its scoped tags. Redeclaring the scope by including the container's tag will create another level of nesting, which is probably not what you want.