I attended a free Adobe eSeminar the other day and learned some good techniques to use when presenting a seminar on a web-conferencing platform.

Some good techniques included using:

Anticipation is created with phrases such as “At last…”, “Imagine…”, “…new…”, or offer and award at the end.
Incongruity with a question and a off the wall answer, or surprising facts.
Participation by asking questions, getting attendee involved in polls, unique answers.
Visuals are understood faster by the brain then words, thus saving time. Visuals are more memorable and keep attendees focused. Select graphics that have a lot of details, are abstract, and show contrast.
Vocal Variety by changing melody and pitch at adjectives and adverbs. Use different presenters. Use different emotions.

Bad techniques include:

Starting an introduction about yourself seems self-indulgent (have someone else introduce you, or put the focus on the attendees)
Bulleted slides
Monotone Voice