Template name space (well since {{pagename}} should work even if the namespace is not defined)
Why do we need the template namespace?
What is a template? (last three points to be discussed in one go)
What can a template do?
Parameters for customisation
Good practices of designing a template
Importing a template
Discuss all the CSS and non-CSS related information (important for the printable format, and mobile screens)
Risks of using a template (example, source vandalism may lead to cascading of it, wherever the template is used)
Possible solutions (information about high usage templates)
Protection of crucial templates
Substitution
What happens when you {{subst:someTemplate}}?
How often should you substitute a template?
When not to use subst?
What are the things you can create now? With the available information during the seminar?
What are the things you can not do right now, but you might have seen it in action. (example: auto-update of age parameter in infobox for living people)
How to make that possible?
Introduce #expr
All the template related magic keywords beginning with "#" (#if, #ifeq, ...)
How to use it? (example from enwn's xQuote template)
Things to consider while designing a template? (cross compatibility, consistency with other projects, ease of navigation and export, desktop-only vs mobile-only vs both, extending compatibility, Dos and Don'ts)