Desperately seeking suggestions: what works best with on-line teaching?

When in doubt, turn to the internet. In a couple of weeks, I'm going to start teaching my first on-line course. So far, I've been preparing by:

1. learning how to use Blackboard
2. getting a subscription to iFinch so we can do bioinformatics in style, and share data and other files
3. getting a microphone and some software for making video podcasts

But, since this is brand new and I'm used to seeing students face-to-face, I have a queasy feeling in the pit of my stomach. I do not want to be one of those people who simply puts lecture notes on a web site. So, I'm turning to you for advice dear readers. Have any of you taught or taken on-line science courses? What kinds of things worked best for you?