a) Get the Right Audience
You'd never be able to sell a laptop to a person looking for a bicycle :-)
Figure out the right audience for your sessions.
b) Focus on Learner's Needs or Interest
Address the needs of a learner. It would let you get their attention and move forward with the session.
c) Inspire Students
Students are extremely talented. Inspire them with your session. Share the bigger picture - where and how the technology is being used, and how it could be used.
d) Engage Students with Analogies and Stories
Students (practically everyone) loves to hear stories. Share with them real scenarios on how certain combinations failed or worked. Use analogies to help them understand topics better.
e) Use Good Examples - Simple but Relevant
Simple examples remove clutter and make it easier for students to understand code. Relevant examples help students understand the bigger picture and its importance.
f) Follow Good Programming Practices
Your sessions could impact how students get started working with technology or topic. Stay away from bad coding practices. Follow coding contentions.
g) Hands-on Exercises or Quizzes
Engagement improves how well the students understand a topic. Try to have a set of hands-on exercises or quizzes for the students to attempt - either during the session or as a follow-up.
h) No Assumptions, Please
The audience could be varied and might not fit the assumptions you had initially when you created your session. Be clear with the pre-requisites of the session and share it before you begin the session.
i) Transparency
If the majority of the students don't fit the definition of your intended audience, be ready to change the contents on the fly. Be explicit and communicative with what you are doing. For example, 'I was hoping to cover a, b and c but since this is the case, let's work with d, e, and f instead'.
j) Make it Fun
No matter how relevant your session is, if it is boring, none would be interested.
Make your session interactive, add humor. Slides full of text are very boring.