I am currently taking 2 master courses in educational technology. In my journey of learning, I  come across some thought provoking issues and practical ideas on the use of etools.  I came across a research paper by Richard Mayer published in the Educational Computing Research journal (2003) and it hit an accord with the way I design, build and work with online elearning tools

Some Design Principles for the Design of Multimedia Explanations

1. use both words and pictures
2. present corresponding words and pictures at the same time,
3. present the words in spoken form,
4. present words in conversational style.
5. avoid extraneous video and audio.
6. do not add on screen text that duplicates what is spoken
7. begin the presentation with concise descriptions of the components,
8. provide signaling for the narration
9. allow the learner to have control over the pace of presentation.

taken from Elements of a Science of e-Learning by Richard Mayer