Good advice given in this thread already.
I’d also like to emphasize the point of being clear about what you want to communicate with each project you show. The less projects you are actually including into your teaser, the more important this becomes.
I’ve found it to be effective to mix up the pacing of the portfolio, i.e. to alternate quick projects with a clever solution that basically explain themselves with more complex, research and analysis based projects.
Personally, I like the inclusion of crafty work as well as it shows your ability to work with your hands.